This has been my long-standing view, and I have seen a couple of posts here that seem to also have sussed what I feel the true problem is:
Turn Battlemaster from a top-down game to bottom-up one.
If rulers & judges would release their death grip on everything and let small groups of nobles go on border raids against each other, or ride off as mercenaries for a cause that interests them or their religion, the whole gridlock thing would be a moot point.
Let nobles have incentives to go loot and attack what is around them. When it goes back and forth for a while, and builds up - viola! reason for war.
The game has always been too much "smoky back rooms" where a few people plan everything. As other posts have pointed out - these people are risk averse, and at the moment there is no reason to start a war for gain.
So - let small groups of nobles go off and raid, and if they bump into a raiding party from another realm, they fight over the right to loot the region. Bring things down to the individual noble level.
Let them role play about it, and RP outrage, or RP bloodlust to go get some loot, or whatever. Let tensions build organically.
Get rid of the automatic fines and the council members shouting to "get in line!" at everyone, and let people go make their own fun.
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I see the recent dev initiatives as well-intentioned, but like The Ice and many other things, doomed to fail because - you can't legislate morality, and you can't force player behavior in Battlemaster
