Just to add some of my opinions to this discussion.
As others have mentioned, I feel power creeps are super creeps. That avenue is not worth exploring imho.
The idea of super structures has been proposed and discussed over time. I have a few comments, some high level and some on the specific proposed structures.
First, I'm not a big fan of super structures because they either centralize empires (if 1-2 structures of a type per player) and/or add another advantage to entrenched players.
I'm against centralized empires because it limits the style of play. Currently it is perfectly feasible to run a decentralized empire across multiple shards and locations. Once you add unique per empire structures, there's a need to build around that location to better protect it.
The other issue is that I'm in favor of veteran players having the advantage of better developed code bases (already a huge advantage), providing veterans with more and more options to "invest" their resources besides GCL and Power creates an ever wider rift between old and new.
Second, regarding some of the practical suggestions:
I'm strongly against teleport or similar structures. The "local" nature of the screeps world is an absolutely essential aspect of it. Portals and frog hopping already provide players with plenty of options to get to a specific locations if they wish to. We do not need extra mobility or power projection.
Temple. Why cancel out the current game challenge of bypassing the 15 cap? It's a good, healthy coding challenge for players.
Super terminal - centralizes empire (see above) - partially covered by power creeps already.
Missile silo. This one is funny. I personally treat my military creeps as missiles. It's not clear what "problem" this is attempting to solve and feels like a bitch to balance.