Killtech
Discutator
nice you revived this mod hydro.
i too think the event system will be the best therefore. the previous disease events had little impact so it reworking them sounds good to me. but however keep one thing in mind: you should prevent that more than one illness can hit a city at once and you must give a city enough time to recover before it can be struck by another plague. otherwise this won't be balanced and might end in unplayability (your cities permanently infecting each other never given the chance to recover)
i too think the event system will be the best therefore. the previous disease events had little impact so it reworking them sounds good to me. but however keep one thing in mind: you should prevent that more than one illness can hit a city at once and you must give a city enough time to recover before it can be struck by another plague. otherwise this won't be balanced and might end in unplayability (your cities permanently infecting each other never given the chance to recover)

Here are some more things I thought about this idea. Now am no expert at balance so take it just as an example. Instead of just having gangs, outlaw MCs and mafia I thought that paramilitary groups and terrorist groups may appear the same way.

every turn
(The citizens feel secure from other countries)