The situation you dislike, I disagree on. I see it as good as it allows conflict to still happen. It seems like the people problem of people going into large federations/alliances forever is more or less impossible to stop so I would rather have a situation that allows for war to still happen.
Mrh? Allows more war? The current situation doesn't allow more war. It actually prevents it.
Personally I hate federation status as it encourages peace a hell of a more than alliance. You were considering to betray a federated partner? O that sucks, you have to fight all of your current federated partners than.
The number of times I have seen a realm leaving a federation and going to war with the former members a is vastly outnumbered by the number of times a realm has left the federation, and then gone back to peace/alliance as soon as allowed by game mechanics. The "leaving a federation = war" mechanic is, mostly, useless, because it almost never happens.