Agreed, 0.89X offers a lot of new features and cool advancements including the possibility to pillage and defend villages plus a ton of new battle commands that make the game a lot more interesting tactically-wise.
Sacrifices of war prisoners will be there of course, it has long been a planned feature (just never got to actually making it) hehe
Now village improvement would be especially interesting if we adapt it to Veracruz, say it would have city improvements that are directly "willing Christian natives- dependent". Of course if we added that, which would be very good, we could go back in time a bit and start the mod when Cortes firstly arrived on Veracruz's coast and start the village and fort with him from scratch.
Native cities wouldn't see much development in their villages, maybe the most we could do is give a fief at some given point to a famous native player warrior and allow him/her to improve it a little bit.. or maybe a lot with that what-if stuff (an iron forge, battlements for the walls, a gunsmith.. ) I guess it'll all depend on how complicated it is to make and all that, but for now it looks like a ton of work to me