About the various "fixes" proposed for MA Ulm.. Well first of all I don't agree that Ulm is broken, or that it needs any sort of fix. Ulm is my favorite, and I think it is a decent nation, with strengths and weaknesses as are appropriate. Ulm has already been upgraded from Dom2 -- the random picks on master smiths are a godsend.
But, at the same time, even I admit that Ulm is not among the top tier of nations by any means.
So, some small improvements aren't a bad idea.
1) The idea about cheap Marignon-style x-bows.
This would help early expansion for MA Ulm, and I think it's a great idea. Certainly not unbalancing, and it would provide a boost. However, I should note that the arbelest is one of the best missile troops in the game, and the cheap x-bows probably wouldn't be used much outside of the first 5-10 turns or so.
2) "A boost to some basic stats - strength, hit points, morale, and endurance."
Not a bad idea, but their troops are already very good. Improving this sort of thing doesn't address Ulm's weaknesses, so I don't see much of a reason to do it.
3) "A bonus to the specific Ulm equipment. Lighter armour, more damage to weapons."
Same as above.
4) "Recruitable troops that are not burdened by heavy equipment."
Same as above.
5) "All restrictions lifted from the extra magic pick. Let them have everything but blood."
Sounds absolutely delicious. This would address a basic weakness of Ulm, which is magic diversity. Wouldn't be overbalancing (because the random is only 10%). Let's do it!
6) Give a +10% chance at a random earth pick.
Same as above. With these last two things, Ulm would clearly become at least a middle-tier faction (especially with the cheap x-bows too), imo, because their forging would go for merely excellent to absolutely out of control good.