Actually, I'd say that since we've already got a package of changes intended to improve the warfare situation discussed and on the slate for being implemented this fall and winter, we should hold off on trying to make any more major changes to the way war works until after they're in place and we can see their effects. Some of them are going to have very large effects on the way people conduct warfare in BattleMaster already (or at least, if they don't, then we've done it wrong!).
I agree. if they are already decided big changes in warfare, the logical way would be to wait the effects of them, before to decide to change it even more.
If you only want ideas to prevent this kind of 'to-death' wars... Well, it could be useful some kind of 'all useful men at arms'. It could generate some big amount of free militia in the capital, with a high cost... maybe to loss a big amount of population, or production, or morale, etc... The objective would be to have a last recourse to defend your realm if its existence is endangered (it would be powerful but highly damaging for the realm), and make the destruction of a realm a very serious thing.
