Actually, I'm pretty sure all the realms currently involved were willing to attack BoM except Talerium. Caergoth just wanted some action, Minas Leon wanted Brackhead, Rieleston wanted to help the CE, and Lyonesse... I think was going to take a small segment of lands? Might be wrong on Lyonesse.
As ironic as it is, Heorot may have saved the Barony. We'll see...
All those reasons make more sense then they wanted Kerwin dead. They all wanted something, obviously, but it wasnt Kerwin or war with BoM should've happened sooner.
I'd be surprised if BoM lasts much longer after Heorot falls given how easy it would be for all parties currently involved just to shift their focus and go after BoM after Heorot is done with. Given that I have no idea who Arnor is trying to negotiate with, though, I can't say for sure.
