I agree with PureBlood. It is easily noticeable that more recently when servers have been added (Inferno, Comp Rotation, and even Assault) they have not been that greatly populated like our older ones. The situation could arise where one server would have 24 people and the other would be empty. Like PureBlood mentioned, everyone would possibly want to try and get in the minigame server because it might be more "fun", but since it only has a capacity of 24 people, that leaves those who are left out to go and wander off somewhere else because they may not have had the intentions of going into the other more traditional jail server. It wouldn't be fair to people if everyone was fighting to get into the more "cool" server and having to settle for the jail that they didn't set out to play. This isn't to say that the minigame jail will be the one that everyone wants to play, it could easily be vice-versa, or even both servers may be heavily populated and favored by the people, these are all just possibilities that should be looked at.
Now on to my main opinion: I don't like the idea of splitting up the people who I play with. Generally, when I go into jail its to play with my friends, whether they are in the clan or just familiar faces that I often see in jail. Having the capacity set to 40 may seem hectic when its full or close to it, but it also allows us to play with more people at once, and when I say people I mean friends and players who we are familiar with, and even those who we are not. I like being able to go into the server and having the opportunity to have fun with 39 other people, sharing the same epic fail or epic win experiences with 39 other people, whether the majority are my friends or strangers.
The idea of breaking this down doesn't seem ideal to me. I would hate to be playing in one server with some friends while others are playing on the other server and having a much better time. People shouldn't be left out. I want to be able to enjoy myself knowing everyone has the chance to be in the same server I am having fun as well, not in a different server unable to be sharing the same thing. This is the point of being in a clan, to experience the same things together, and there is nothing I enjoy sharing more with my clan members than the epic fail and epic win moments that happen often in jail.
For me, if eGO is a big caring and mature family living under the same roof(server), why split the house in two?