the only issue is, i'd much rather people had the freedom of playing whenever rather than restricting it, but if they prefer quality over playtime then hell yea might aswell do zeus
Keep this in mind, Zeus can allow freedom to players, all you have to do is give them tasks to do, and while they do all you have to worry about is making them have a hard (but fun) time.
Unless we were looking at something like 20 players I think some Zeus stuff isn't gonna be much fun. The enjoyment for me is working from the ground up with basic shit and eventually reaching powerful levels right at the ultimate endgame, not having full tactical gear from the get go and wiping the floor with everyone. That's just my stance though and why I'd prefer Antistati/Armia Krajowa though; choice is up to Surrator at the end of the day.
iirc there's plenty of players, but for smaller groups Zeus and premade missions are usually more enjoyable than Antistasi
The 'endgame' you talk about is something I've experienced myself with 6 friends of mine. When both factions are at a 100 aggro and you're at War Level 10, plus many locations captured, it turns into a hell of counterattacks, assaults, incredibly strong enemies and so on. You'd prefer to either have the game be easy difficulty from the start, or having enough people not to force everyone to grab a team of 20 useless AI to assault places without dying 10 times per attack.
AI skill can be improved up to 20, but it takes a shitload of money to do so, and it's still shitty AI, only difference it makes is that the enemy won't wipe your airbase with 120 AI in it, just half the numbers.
But keep in mind, with the amount of players we have here Antistasi is a pretty good choice, though the PVP slots (USAF/AFRF) would have to be seriously controlled or people's gonna be pissed.