I'd rather just have the starbase allow me to 'order' the modules I want from the list and then summon the necessary constructors, tbh. Do that and remove the 'basic' versions, and we get the best of both worlds; those who want to automate it can just lay out what they want the starbase to become on placement, while those who like constructors can continue to tailor them as they do presently.

Do we? I generally just use the best one that's available, based on the modified blueprint I use. The main reason for having half a dozen variants is due to the base model and the blueprint being fairly awful.

I don't disagree with letting you pick the 'favoured constructor' module, or picking a shipyard to male the constructors, but I genuinely don't use more than 1 version of my constructor ship on purpose at any given tech level in the majority of games. Just having the 'basic' version work as a blueprint (one that wasn't designed by someone with a strange fetish for life support modules and an aversion to engines) rather than a flat ship type would probably suffice, tbh.

Agreed that most constructors fall into the design of "best single engine, no life, no sensors, max constructors", but there are scenarios where you might not want to follow that design:

-starbase is in contested enemy territory, where more engine speed drastically improves its chance of survival to the starbase.

-the shipyards near your starbase are soley focusing on military vessels, and the only avail shipyard is very far away, hence you might sacrifice 1 constructor for more engines

-you may only need 1 constructor for a very long time (a single SB scenario, not a cluster of SBs in which a multi-constructor is often used)

Granted, these still are not the common use.  Perhaps allow one to select as I have proposed, but also allow an option to disable this per starbase and select a "preferred" constructor design.  The preferred constructor selection would be an empire wide decision, not a per starbase decision.

Yes, but the evolution algorithm would then later be a source of debate.   Better to allow you to choose it, after you decide to design your next line of common constructors.  A few added button clicks every few dozen turns would be a nice compromise to snuff that issue before it even starts.

One thing that would hugely help with the starbase spam is to make mining rings work like the Xeno-Archaeology line. I.e. can fit on any base. Then you'd see a lot less starbase spam because you could cover the same ground more efficiently. I'm not honestly sure why their separate. Lets be fair even a fully upgraded starbase has crap for defences so it's basically helpless in an actual fight they seem to be there to limit the power required to kill them, not make them tough on their own. So i don't see any mechanical issues with them working that way. Anyway think of any mechanics that would break down?

Just to pipe up, I build lots of different types of constructors.  I build double constructors, triple constructors, far constructors, fast constructors, and cheep constructors.  One faction has two cheep constructors pre-designed.  One is based on a cargo hull, and a cheeper constructor becomes available with small hulls and some miniaturization.  When the cheeper constructor becomes available, I obsolete the first one and make the new one the default minimum constructor.  Some constructors chase relics.  Others fill in economic starbases.  If I ever find a real use for military starbases, there will be a category of constructors called camp followers, constructors who can keep up with a moving fleet.

I do a similar thing with transports and how many transport modules or engines they have.  There are only  three design variants for colony ships, minimum, fast, and far. 

No idea if any of this is useful in my games, but it feels so.  My point is that indeed some people do design and fiddle with constructors.  No idea how many, but at least one. 

That's one of the first changes I implemented tbh. I think it's fine to either have mutually-exclusive rings OR the exclusion range, but both is just overkill.