Well, seeing as how this seems to be over, I'll post my thoughts on Skaven and Brettonia now.
Skaven: First, I like the feel and theme a lot. This is a beautiful mod. Also, I managed to accomplish my main goal for the game: not be the first to die.
That said though, the early game is just incredibly weak. Your troops are just not good enough to carry you, particularly on a NI map where you can't hire any arrow catcher indies. Anyone with arrows is going to rape you utterly. Yes, I know that Skavenslaves and/or plague monks can be decoys, but once engagements reach a certain size, they just die too fast to be effective. Even when you make it to the enemy lines, you take a ridiculous amount of casualties. Your armies are nowhere near sustainable. While your mages aren't bad, the lack of decent blockers hurts. Your summons are okay, but the warp_ throwers seem to be bugged, as they had a tendency to run straight into melee without shooting. Of course, its entirely possible that a better player would be able to come up with a killer strategy. Still, I think that the very weak early game severely restricts your options.
Brettonia: While of course llamabeast will have the best overall view of things, I will still make a few observations. First, freespawn archers are perhaps a bit much, particularly against Skaven. Second, having what amounts to an income and resource independent recruitment is a difficult thing to balance. It might have been interesting to see how they might have done had llama been able to recruit damsels in his cap every turn for a respectable research.