Couple things I would like to suggest:
1. Making it so people not in government can fight as units. This would make it so you don't have a bunch of people who are useless beyond whichever 5 or 6 you may use throughout the game.
2. Auto-leveling, bc leveling up everyone late game is awful.
3. A marker for when you've hit max height/dick size, like with boobs. Those two seem to not have a cap for some reason? Idk
4. Maybe lowering the happiness/religiousness max/mins so that the gains and losses are more meaningful? At 2000 you can lose a ridiculous amount in one turn and not care. I'd personally do a 0-1000 but it's obv up to you.
Questions:
1. Does Arena/Regular Reputation do anything? I can't see anything besides flavor.
2. Is there anything to government people like Captain Boot/Dominatra as Head Priest beyond flavor(not that I don't love it)?
To your questions:
1. The Arena reputation is currently fluff only, the regular reputation slightly modifies some events, but not in a dramatic way
2. No, not right now but probably in some future version
Regarding your suggestions:
1. So first of all in the new version that got released this week on patreon (will be available to the public in two weeks), there is something more you can do with your prisoners and followers - you can have them work in the brothel and earn money for you. Aside from this, I have thought several times about making them available in your army and ultimately it boils down to being really hard to balance, which is why I have shied away from this so far.
2. Yes, auto-levelling on my todo list, unfortunately, it did not make it into the last version
3. There is no max size for dicks and height because some people just want them bigger and bigger and it seems no matter how large I allow it there are always players that would like their dong even longer, so I just went with no limit
4. That's an interesting point, I will think about it