I think the general idea is that you want to have tech trees to be reasonably balanced.

One tech which I think is a little too powerful is the Factory tech tree. No doubt you have to research this branch like crazy. However, I feel like this tree is also made more powerful by the inclusion of the starbase factory technologies. It just makes researching this tree even more critical.

One suggestion might be to split the starbase factory tree into a new technology branch. (orbital production, advanced orbital production, etc. etc. etc.)
This branch would do two main things -- 1) the economic starbase production (mil / soc / research) branches. and 2) the resource mining improvements.

Another way (my preferred suggestion) would be to break the economic starbase function up entirely.
Make a starbase module that would be +7% purely military (further tech upgrades would be another +10%, +15% etc.). Another module that was purely +7% social. Another module that was +7% research (preferably in another tech tree).
This way you could specialize your starbase / planets as well. This starbase could effectively turn the area into a major shipyard. Or maybe this is a research station for a set of research worlds.

I think forcing players into making these choices adds flavor to the game. As it stands, you can't go wrong adding constructors to an econ starbase and raising all production levels up to max. If you have to re-gear for wartime production or research -- it all doesn't matter. Plus, the upgrades seem pretty generic and uninteresting. +3% +5% +7% +10% etc. Force players to scramble -- make peaceful players have to suddenly upgrade their orbital ship-building facilities.

Just a thought.