And I hope, but very much doubt it will happen, that the trainers will disable Online functions. So no easy Platinum trophies or MP matches, although the Jailbreak could start bots running MP games.
Regarding aimbots, it's not a cheathappens problem. They only do single player trainers and those trainers would be tailored for single player only, so you won't find people with unlimited health online.
Regarding the trophies there are already utilities that unlock every trophy, so if someone wants to do that they can already o it. Thus, there is no need to worry about that either.