Zenith Traders: Since they sell Warp Gates to the AI, they can potentially cause infinite AIP growth. How big exactly is this problem?
Zenith Miners: Permanently losing a planet is bad. Permanently losing a planet every few hours is game-breaking. Do the miners ever die out?
Human Colony Rebellions: Do they cause AIP reductions? How far away can they spawn? And how often can they spawn during one game?
Neinzul Rocketry Corps: They sound like fun on one hand, and like utter hug on the other. What AIP effects can these little guys have?
Spirecraft (3 - Hard, accept no substitutes): How easily are these lost? Irreplaceable ships are a questionable thing for superlong games, unless they're supertough.
Spire Civilian Leaders: So let me get this right - I capture enough of them, and AIP goes down. Perpetually. I can just wait and watch as the AI withers and dies?
Furthermore, AI plots.
Advanced Hybrid Hives: These guys can re-colonise planets for the AI. Which, I suppose, is at least another 15 AIP to add to the list. How frequently do they do that?
Thanks for any help.
Zenith Traders: Right now, I think their sell chance to the AI is 10%, which is WAY too large, especially for the pace you seem to be aiming for, or even the "normal" pace that the game is balanced against. But potentially giving the AI more stuff that it values or is really tough is part of the risk with this faction. In return, you get some really cool stuff.
Zenith Miners: I think they recently got a buff to their spawn behavior to make them more threatening. They may have gone too far though...
Human Colony Rebellions: No idea about spawn rate or spawn caps. No they do not cause any AIP reduction on capture. The only bonus you get from it is a small amount of extra resources and the ability to build human rebellion ships for yourself. If you already have a very powerful fleet, then this minor faction is probably more bad than good.
Neinzul Rocketry Corps: Thankfully, AI and Minor faction versions of warheads do not give any AIP increase.
Spirecraft: Most of them are, thankfully, durable enough to be usable (Especially on easy or hard, where most of them are repairable). The suicide ones (the martyr and the ram) you can of course expect not to live very long, but the other do pretty well. The penetrator even has perma-cloak unless it is reloading its weapon. (There is discussion going on about how to make spirecraft shield bearers not be so useless at low health, due to the fact they can NEVER be repaired. Personally, I like the idea of giving them a minimum shield size >> 1, and only hit that minimum shield size once HP hits 1.) Keep in mind though, like any tough ship, they can die if you don't know when an attack isn't going so well and start retreating early enough to make it back to friendly territory safely.
Spire Civilian Leaders: What Zeyurn posted is right. The AIP floor keeps this from reducing AIP all the way down to 1 for the whole game. And AIP floor will grow when things happen that would normally make AIP go up, even if the amount of "accumulated negative AIP" you is enough to overcome the "accumulated positive AIP". So no free forced low AIP for you
. However, keeping the AIP at the floor is still very helpful compared to letting it grow normally.
Advanced Hybrid Hives: Wait, the tool-tip still says they can recapture planets? That is currently wrong. They do not, thank god.
EDIT:
In short, yes, some of these have the potential to force you to keep bumping AIP (or at least the AIP floor) up, but that is part of the intended design of the game. The AI will consider you more of a threat as you keep going throughout the game, no matter how well you try to sabotage them. Before you complain about the "one true pace" thing again, the minimum pace of the game if you can manage to keep AIP very low, or maybe even at the floor, is VERY slow. If you are good at keeping AIP low, you can have VERY long games to play around as you wish.