[Mightypeon]

I think we may be partly talking past each other here.
Yes, the effect that crossbows have in a battle can diminish greatly with Protective Magic, yet in my opinion, the same happens with most if not all national units.
Movement 2 and the Siege Bonus are never truely outdated however.

But then, I have not been in the situations where Arbalests are most heavily desired yet and I cannot comment on the full scape range 45s tactical abilities so it is well possible that I underestimate Arbalests.

Would you agree with the statement:
If you wish ranged fire support as MA Ulm, usually go with Sappers unless there is a direct reason to go with Arbalests?

I also want to thank Soyweiser for correcting me about upkeep.