Have faith, things are continually improving.  Just because this expansion didn't have your hot-button feature doesn't mean there isn't lots of good content.

Think happy thoughts. 

This may be true, however, think of what this game came with compared to Galactic Civilizations II when it was first released.  Galactic Civilizations II also did not have the ability to create a custom faction so therefore what you see is what you get only 10 factions to play with with no custom tech trees.

Galactic Civilizations II Core Factions

• Terran Alliance
• Altarian Republic
• Drengin Empire
• Yor Collective
• Thalan Empire
• Iconian Refuge
• Arcean Empire
• Torian Confederation
• Drath Legion
• Dominion of Korx

Galactic Civilizations III Core Factions

• Terran Alliance
• Altarian Republic
• Drengin Empire
• Yor Singularity
• Thalan Empire
• Iconian Refuge
• Krynn Sindicate
• Irridium Corporation
• Custom Factions (Creates Endless number of faction possibilities)

So with that being said, although Galactic Civilizations III base game came with two less core factions, it came with the ability to create custom factions.  With that being said each has it's own tech tree and unique abilities.  Personally I'll trade to core factions for endless custom factions any day but, that is to each person I suppose.

Let's look beyond the base games, shall we?  

Galactic Civilizations II later added 2 additional core factions (bringing total to 12) with the custom faction as well, each with unique tech trees, and this was after it's third and final expansion several years after the release of the base game.  Galactic Civilizations III has already added 3 core factions (bringing total to 11) to the base game less than a year after release.  If one purchased Galactic Civilizations II at release with expansions at release they would have purchased the game for $100 (approx I don't have the actual release prices based on $39.99 for base and $29.99 for expansions each).  With Galactic Civilizations III one would have purchased all DLC's and the 1 expansion to this point less the soundtrack you would be at $90 ($49.99 base game, $4.99 x 4 DLC's, $19.99 expansion).  Even if one would add the $9.99 soundtrack you are right at the cost of $100 and, you only need to purchase what you want.  If you're a founder than you already potentially paid the $100.

This I agree with but, I'm okay with the design plan for the game to this point.  Hopefully it's right around the corner in the near future

That's not true. The ability to create custom factions was in GalCiv 2 from the start.

No, they weren't. DA added the ability to play against custom factions, and provided more options to customise them. However, you could already play as a custom faction in DL. Just start up DL, if you don't want to believe me.

Here is a link to Frogboy's Beginner's Strategy Guide for DL. The second screenshot clearly shows the custom race option (mesh-figure in the upper right corner). I also still have the manual of my retail copy of DL, and it mentions the ability to play as a custom race (not sure, if I'm allowed to scan the page in, so I could show it to you). The wiki-page for DL also mentions it (though wiki is generally not a trustworthy source). Lastly, as I mentioned before, you can simply start up DL without any of the expansions. The option is there. 

I think its still a point in Gal Civ III's favor that it started with the option to play against custom opponents, because right now through steam I have downloaded about 30 to choose from, and of course the option to pick from hundreds (thousands?) of pre-made custom opponents already created, as well as make my own of course. So yeah the potential opponent list for vanilla Gal Civ III is not 8 or 12 but basically unlimited.

However I agree with the OP about planetary invasion being bad and hoped that was what was to be addressed in the expansion. I hope it gets overhauled soon.

Because custom races were player-only in DL. You couldn't select them to play against. That's what was new in DA.

Stardock has made a distinction between dlc, expansion, and expandable. Steam has not. 

For me, the above is what's stopping me from playing the game or buying more DLC. I wonder when they will sort it?

Wow you are missing out on things other games only touches.