Nah.... the structures that require strategic resources need to be beneficial enough to put pressure on the player to set aside the resources for it..... otherwise players will prefer to use those resources elsewhere.

We don't need to add more structures to the list of hardly useful structures already in the game.

Personally, I like the power of strategic resource improvements.

 

It is the reason why resources have to be mined. The advantage must be consequent, if no, why to play with resources ?

I think the resources are also usefull to get mercenary ships, or to build very strong warships.

Instead of modify these improvements, may be an option in the game settings could allow the player to choose the power he wants for the resource improvements (very small, small, normal, high, very high).

Since it would mke it better I think some kind of leveling sytem for improvements would help. Please keep the adjacencies to at least +2 , or I probably wouldn't use resources. 

I have decided to compute the power of these 3 improvements: durantium refinery, promethion reserve, and thulium data archive.


1. Without adjacent bonuses.

In the middle-game and end-game, a farm gives arround +6 base population, so +12 with a 100% population bonus. And +12 to the base raw production, so +24 with a 100% raw production bonus.

As the raw production is distributed in the 3 sectors, a farm gives +8 to each sector. The resource improvements also give +8, but in only one sector.

So it is much better to build 3 farms instead of these 3 improvements without adjacent bonuses.



2. With adjacent bonuses.

For an economic planet we can expect +9 from adjacent bonuses and 321% from the improvements that gives these bonuses.

We have a +17, which is the quivalent of arround 2 farms, but it takes 7 tiles.

So, for an economic planet with 7 starbases (the planet have mostly food improvements), we have on one side a loss of 5 farms and +321% to the economy, and on the other side a loss of 7 farms and so a reduction of research and manufacturing.



3. Tests.

I wrote a program to compute approximatively the production of a planet, here is the result.

For an economic planet with 17 free tiles and 7 economic starbases:

- without promethion: 1310 (economy), 1047, 1047
- with prometheon: 1590 (economy),  760,  760

So +280 to economy and -287 to manufacturing and research. And if I compare to an unspecialized planet that have a production of 1250 in each sector, then there is +340 for economy, and -490 in manufacturing and research.

For the same planet without starbases, omitting the approval:

- without promethion: 600 (economy), 286, 286
- with prometheon: 750 (economy), 262, 262

So +150 to economy and -24 to manufacturing and research.

 

I may have done some errors, but I finally think these improvements aren't so powerfull, specially in the middle-game and in the end-game.

 

4. Levelling the improvements.

I think they should be levelled in 3 levels in function of research techs, for example:

Durantium refinery: +8 and +1/adjacent bonus
Mega Durantium refinery: +16 and +2/adjacent bonus
Ultra Durantium refinery: +32 and +3/adjacent bonus

+32 seems to be a lot, but in the middle-game or end-game, building these 3 resource improvements together, without adjacent bonuses, only corresponds to 4 farms, so a gain of only 1 farm, for a population loss of 36.

 

With this levelling of the improvements, my program give the following results still for the economic planet, with a +32 bonus, and this time all these 3 improvements, because in this case they are better than a farm:

- without resources: 1310 (economy), 1047, 1047
- with resources: 2010 with a +3/adjacent,  1187,  1187

So +700 to economy, and +140 to manufacturing and research. But a loss of 6 farms (72 population less), so the planet will be easier to invade due to a low resistance, and the weight of the empire will be much lower for united planets.

 

For the same planet without starbases, omitting the approval:

- without resources: 600 (economy), 286, 286
- with resources: 962 (economy) with a +3/adjacent,  358,  358

So +362 to economy, and +72 to manufacturing and research. But with 5 farms less, so 60 population less.

 

These bonuses may seem to be too high, but I think in the early game, these resource improvements give a bonus of the same order compared to the production without these improvements.

So, with this levelling of the resource improvements, they will still be very usefull in the middle-game and in the end-game, making the use of resources very strategic.

I may have done some errors, but here are the numbers for a research planet with 24 free tiles and 7 starbases:

- Unspecialized: 1749 (research) / 1749 / 1749     (24 food)
- without thulium: 2283 (research) / 1187 / 1187     (16 food, 8 research)
- with thulium: 2615 (research) / 1047 / 1047     (14 food, 9 research, and one thulium data archive)

So a +332 to research and -140 to manufacturing and economy. And compared to the unspecialized planet: +875 to research and -700 to manufacturing and economy.

Without starbases, ommiting the approval:

- Unspecialized: 598 (research) / 598 / 598     (24 food)
- without thulium: 1253 (research) / 358 / 358     (14 food, 10 research)
- with thulium: 1451 (research) / 286 / 286     (11 food, 12 research, and one thulium data archive)

So +202 to research and -72 to manufacturing and economy. And compared to the unspecialized planet: +851 to research and -310 to manufacturing and economy.

Thulium Data Archive seems to be a good choice for a strategy without starbases, and considering food planets needs a lot of approval that is normally given by the starbases, so the numbers I gave for the planet without starbase should be in reality lower, and the advantage of the Thulium Data Archive should be higher for this planet because with Thulium the best solution to maximize research requires less food improvements, and so less approval improvements that do not increase the research production.

I didn't computed precisely, but I think resource improvements are also a good thing for high class planets, that even with starbases, can't be totally filled with food improvements, the starbases not producing enough approval for them. So I think you are right to build these improvements only on high class planets. And so, I finally don't agree with the OP that says these improvements should be built on every planets.

But I still think resource improvements should be levelled with upgrades to be more powerfull for the middle-game and for the end-game, and to be not reserved to high class planets or capital planets.

I also use resources improvements for a few planets, my capital planets: manufacturing capital, economic capital, research capital, and entertainment capital with virtual world, where I group some high adjacent bonus improvement arround the resource improvement. But my priority is to grow the bonuses of Singularity Power Plant, Virtual World, and Galactic Stock Market, because their bonuses are civilization-wide, and not only for the planet.

The bonus of the Omega Research Center grows by only 1% by adjacent, so I don't know if it is better to group the high adjacent bonus improvements arround it, or to regroup them arround the Thulium Data Archive.

 

EDIT: At the end of this post I give the numbers computed with the approval. I found a bug in my program, so the previous numbers are false, sorry for that.

On this planet there are:

- 1 innovation complex.
- 7 discovery spheres.
- 1 biomass resequencer.
- 15 last level farms.

And I add a +200% bonus to each sector coming from various sources (it is an approximation and I don't remember where does these bonuses come from). In the following of this post, I recomputed with a bonus of only 50%.

Yes, I computed with a +16 for Thulium Data Archive.

No, because I computed for the middle-game or end-game, and I don't have a savegame with enough techs and bonuses.

But here is where I got the 100% bonus for the raw production:

First: 5%, 10%, 15%, and 20% from the governance technologies. So a total of 50%. (If I remember well, these bonuses are each added, but at this time I can't check because in my actual game I didn't already get these techs).

Second: 25% from High Approval bonus

Third: I don't remember where I took the remaining 25%, may be an error I got due to the death furnace that gives a 33% bonus to only one planet, or an error if I took for my computation a planet that got a raw production bonus from a colonization event. I don't remember if there are other raw production bonuses in the game.

For my computations, I took the 35% from starbases in more of the 100% bonus.

You may be right, I can't remember If I modded these improvements, because the mod directory doesn't work on my computer, so I modded the game directly in the game files, and I lost the original files. May be I got this idea because in the past, the original game gave the bonuses from adjacency to every planets.

EDIT: computation with approval:

I tried to compute with approval, here are the results.

For a planet with 21 free tiles for food and research improvements, with the following bonuses:
- 10 as base population (5 from colony, and 5 from various bonuses)
- 50% for each sectors
- 75% to population (50% from resequencing center and 25% from various bonuses)
- 75% to raw production
- 70% to approval (an intimidation center, a missionary center, and a preparedness center, that aren't on the 21 free tiles)
- an average of 80% for a discovery sphere or an innovation complex
- an average of +8 approval for a stadium

I may have underestimated the approval, because I didn't counted the mega resort that gives a 25% bonus and +3 adjacent, I didn't counted Harmony cristals, nor the virtual world, nor the entertainment capital that gives a global 25% bonus.

With 7 economic starbases:
- unspecialized: 549 / 549 / 549    (14 food, 7 approval)
- without thulium: 908 / 329 / 329    (8 food, 2 approval, 11 research)
- with thulium: 1063 / 329 / 329   (8 food, 2 approval, 10 research, 1 thulium data archive)

+155 to research and -0 to economy and manufacturing, so +17% and -0%. And compared to the unspecialized planet, +514 (+93%) to research and -220 (-40%) to economy and manufacturing. It may seem to be a good deal, but probably depends of the strategy, for example if a player wants each planet to sponsor a shipyard, a loss of -220 in manufacturing is a lot.

Without starbases:
- unspecialized: 109 / 109 / 109    (11 food, 9 approval, and one free tile)
- without thulium: 404 / 63 / 63    (6 food, 5 approval, 10 research)
- with thulium: 514 / 45 / 45   (4 food, 4 approval, 12 research, 1 thulium data archive)

+110 to research and -18 to economy and manufacturing, so +27% and -28%. And compared to the unspecialized planet: +371% and -58%. Without starbases It seems to be a good idea to specialize the planet, moreover with thulium.

I hope these numbers are correct this time. About the numbers in my previous posts, I was multiplying the +16 from thulium data archive by the raw production bonus.