I'm following this game for early beginnings and i must say that i love this changes. I like to comment on some of your sugestions.
1. Getting to easy new characters is also not so great. And you can just buy what you need. But it could be nice that if you find someone in the wild that the chance for something worthwhile would be better. But still it could make exotic slave trader useless, so i think it's nice as it is.
2.I'm personally don't miss it. I don't like to much of micromanagement. Everything is going in good direction but i would love if costume and armors didn't took out the same slot. I would rather assume that the slave changes her into armor when she goes for a fight and keeps her outfit otherwise.
3. There already is soft limit for that. You need to invest more and more experience for each aditional class and cost is reduced greatly from growth potential until you exceed the limit. So i don't think there is any need for that.
4. It's changing in that direction already, so no worries. But more difficult content for late game is always nice.
5. It would be nice as an optional choice.
6. I'm still exploring this newest loyalty system. But first impression are great and i think is that the gaining speed is nice. Maybe increase the prizes of more special loyalty upgrades?