Prisons

Yup, careful thought would have to be applied to make sure the feature couldn't be abused.

My motivation is mainly to find some way to overcome the tedium of having to recapture new oasis pretty much every day - there are so many dull repetitive tasks in the game that don't give any reward.

Having prisoners die over time would make sense, anything that increases the number of proper battles will make the game more interesting.

Yeah capturing oasis can be tedious, but it prevents the game from becoming effortless. I think its only fair that there is a price to pay for building a huge army, and supporting it should take some skill and work

Good idea