I've played with Judges most of my time in BM and I must say that the experience is no longer as enjoyable as it used to be when we had more players. Many realms - most of them - have a system of gold distribution... the fines are now purely to lead by example and has no real monetary impact. On the other hand, most of times a ban has a disproportional effect to the "crime" and even so, it's the the only option. My suggestion, and it was always something I had in mind for a long time, would be the option to arrest someone of my own realm. Two days is more than enough. And while you can improve the "prison game", that would be good. People will have more reasons to protest your decision and that will bring much more intra-realm disputes.
About the exile, you can allow a new kind of exile agreed among Judges. If two Judges agree, you can force a prisoner from realm A to join realm B (where he's imprisoned) and once he's released, he can have a chance to start a new life in his "prison", after all, you're a noble arrested in battle, not a poor criminal. It can be good for Dukes, Lords and Rulers, for example. The new realm will be his prison, but you can grow there... this way you don't punish someone excluding him from the game itself, because most of times, this is what happens when you're in prison.
For many old realms, gold is not a problem anymore. Nor it is for old families with a lot of gold to avoid a situation where you will stay in prison for 40 days... instead, you can allow Judges and Ambassadors to use the new treaty system to release a prison after some agreement is fulfilled.
But there is some problems with the idea. You must realize that old people will avoid battles even more... and maybe anyone in a power position will avoid it too. If there is a lack of battles and wars, this new system can be another reason for old/powerful people avoid battles and wars. I have two Dukes... if for some reason I get locked for 30 days with two chars... what do you think will happen!? People will just leave the game... and what the problem with old people? I know realms that without them, the entire realm will crumble and I doubt it will be good for the young people. You also must realize that we don't have realms with 100 people engaged in grow up like we had in the past. In some realms we don't have people even to be our Marshals.