Here is my solution:
- SttC gives less resources (let's say half)
- All planets strip to asteroid...asteroids, dead asteroids, and pirate bases don't strip any lower and give no resources....
What does this do?
As VL in eco, stripping early game is still a good option, but it isn't the obvious option...currently, a VL in eco just always rushes strip, strips a planet or two near center of map, gets titan and kostura, and goes and kills things...halving the income you earned from SttC helps you get titan faster but it doesn't put you so far ahead of everyone else...it makes the VL in eco consider their options without nerfing SttC into oblivion...
As VL in eco, stripping mid-game (when you have titan and/or kostura and going on offense) is still useful...you are taking away a good enemy planet (probably another eco player's HW), and getting some resources from stripping it...however, the stripped planet is still an asteroid, so after the VL retreats or moves on, the defender still has something to put structures on...
As any VL, stripping late-game is not nearly as OP as it is now...you still get a nice feed of resources, but with only half as many, it's still a good idea to have a regular economy...also, because you can't strip below an asteroid, you can't "cleanse" sections of the map and completely wipe players' planets...even if you strip every planet, unless you magically are able to simultaneously hold all those gravity wells, the defender can always recolonize those asteroids and put up structures...
Your solution:
- SttC is low level tech (lets say around tier 3)...coming off of it is a chain of techs that increase the resources earned
- Income earned via SttC is taxed
As VL in eco, you aren't going to have any problem getting all those techs quickly...even with SttC as a tier 8 with 3 mid/high level prereqs, eco players easily get SttC early on...simply changing what techs you need isn't going to change things in the slightest...also, the taxation part does nothing to prevent you from getting uber resources early on...eco player has no fleet upgrades (maybe 1) so the first two planets they strip still are going to give them a titan and kostura pretty quickly....
As VL late game, let's just say your taxation rate is ~50%....you are getting the same amount of resources you would if you had just halved the base income...no difference late game...
Taxation also does nothing to prevent you from wiping players...but even if you combine taxation/different techs with no stripping below asteroid, you still have done nothing to prevent VL eco players from abusing this like none other....
Additionally, by allowing SttC early game, frontliners can now get it as well...sure, maybe they can't upgrade SttC but that hardly matters...suicide players getting double teamed could colonize some planets, get some quick cash from the extractors, and then strip as soon as they realized they couldn't hold them...frontliners could just start with two caps, bomb out the nearest enemy world, strip it, then retreat with impunity....and if a frontliner is losing a planet? Strip it, retreat with extra resources...by having SttC so early, you have denied the enemy easy sources of income at no loss to you (cause remember, you couldn't hold them anyway, that's why you left) and have prevented them from being able to get as many factories close to your HW...
Taxation and tech upgrades to strip do nothing to prevent this from being OP for early game eco VL....they make SttC more OP for early game frontliners and suicide spots, and they are equally successful late game (assuming you also keep the asteroid rule)...
So what do I mean by simplicity?
Well, simply halving the earned income combined with the "Asteroid" rule stands a good chance of solving most of the problems with strip...one might say you still need to make strip harder to use (maybe it takes longer to use, or requires a titan ability) but it would be a vast improvement over what we have now...my solution is simple, requires no engine change, and I'd argue would be very effective....
Your solution not only requires more work (new techs and engine changes), but actually makes SttC more powerful early game with no late game offset...even if you tried to "balance" it by making it harder to strip, etc, you are complicating the situation far more than it needs to be...I won't say it is impossible to balance but taxation is completely unnecessary to make SttC viable but not OP
Why implement a system that requires engine changes and is going to be a pain to balance when there is a simpler and more effective alternative?