I like the suggestion of a larger bank, but maybe we need to look at the tactics for taking down heavily defended core worlds. Look at what's causing fleet wipes, and if that's just not supported.
That's actually a good point. Are fleet wipes a common thing (well, common enough to get a 4 page thread about it) merely because the punishment for it is rarely more than just time loss, or is it because the game (whether by the engine, the unit/structure design, whatever) doesn't really give many other options that given similar sorts of long term gains?
It it is the first, then this isn't such a huge deal. The AI's responsiveness could be turned up, and maybe economy could use a bit of tweaking, but its not like a huge flaw, just a playstyle that lots of players gravitate towards.
If it is the second, then that is a sign of a much deeper problem with unit/structure/defense design or possibly even engine design, and will require significantly more thought.
The "dynamic resource cap" idea is pretty cool in either case. Maybe do something like bump the base resource cap back down to 300k (each), but the HW command center adds 200k (each) to the cap, meaning for the typical start (1 HW start), a player starts with a 500k cap. Then, other command stations would also add to the cap, but to a lesser degree (like maybe the Econ Mk. III would add 150k (each), but Military Mk. I and Warp Jammer would be at the bottom only give a piddlin 20k (each)). Then the spire hub could give like, idk, 200k (each) to the cap, with each habitation center also giving an additional 150k (each)?
This would also have the nice side effect of a long requested feature, increased resource cap for multi-HW starts, as you would have multiple HW command centers, each giving 200k (each). Also, the command center cores would should probably still increase the cap, but by a much reduced factor, like only 100k (each).
Of course, numbers will probably need to be tuned.