Would be interesting if one of the elements they added was prisoner wealth...I mean would be interesting to have some rich business man bribe you to build him a luxury cell or something of the sort
or something like gangs and "prisoner interest groups"? i.e.:
one "wealth seeking" prisoner has the desire to pile up wealth so he runs around stealing stuff. maybe another prisoner gets angry because he stole something from him and confronts the wealth guy with his fists.
then the wealth guy "talks" to some muscled prisoners of the "fitness room" group (who mostly spend their freetime in the fitnessroom) to be his "bodyguard" forming a little 3 man group who mostly stick together when possible.
maybe he steals again from the guy who first confronted him, but this time the 2 muscle prisoners guard him and beat the other guy up a bit.
the beat up guy might talk to his 3 "laundry group" friends and a little riot breaks out in the yard between the wealth guy and the laundry guys... all that causes the whole cellblock A where both groups live in to be on lockdown for a while...
the lockdown might cause the claustrophobic prisoner (he mostly spends his freetime in the yard), who didnt had anything to do with the riot but who lives in the same cellblock, to go kind of crazy and talks to the "religious group" (a few guys who mostly pray in the church) for help... the religious group is also a secret major drug smuggling group and gets the crazy guy on drugs for money... what might cause him to smuggle stuff to the "wealth group" for money to buy more drugs from the religious group... etc.
maybe groups are build slowly when prisoners are often in the same areas or their cells are near eachother.
or prisoners with similar interests (religion/fitness/books/wealth) could form groups.
or prisoners who are working in the same area (kitchen/laundry/cleaning/etc) form groups.
or prisoners with similar criminal history could form groups based on that i.e. theft/drugs/murder/etc.
or prisoners who dont like what you do to them group up against the prison.
and maybe more evil/criminal groups start as "secret/hidden" from the player i.e. the religious drug smuggle group and it would take a while of observation and investigation to find out such a group exists in your prison. or a group who wants to try to riot, or a group who wants to dig out a tunnel together to breakout.
other groups could be more public like the muscled fitness group who always stick together at yardtime and go to the fitnessroom in their freetime. well or the public religious group who is hiding that they are drug dealers too.
maybe groups could even "demand" stuff from the player... i.e. the religious group wants 5 more bookshelves in their church to make them more happy... (and to have more books to smuggle the drugs around your prison).
or the fitness group wants a bigger fitness room with 6 workbenches.
and you can either fullfill the demands or not with different results. (maybe a bit less drug smuggling because they dont get more books.)
or the groups could bribe the player/guards/administration. (i.e. the wealth guy might bribe the guard of his cellblock to lockdown prisoners who did lend money from the wealth guy but cant pay their loans. and the player might not get informed of this... the player might just see a guy locked in lockdown for no reason and has to investigate whats up.)
different groups could also like and hate different other groups... maybe they mostly try to stay in their own groups and as far away from other groups at i.e. yard time the groups group up away from eachother in different corners or stick to the same table at lunch etc.
depending how much they dislike eachother they could bully the other guys or blame them for something or have fights.
groups could add a ton of interesting stuff to the game... it could also open up room for new buildings i.e. fitnessroom/church/pool(?)/libary... just imagine the "prison tv series" and how people group up in there.