Thanks for pointing that out (also @Grugnorr). The arbeletiers are crossbows for sure. The description makes the arbeletiers sound like they also have a defensive shield deployment capability, which I would think works similarly to the longbows’ palings. Of the French unique units, the arbeletiers is the one I’m most intrigued by. Presumably, the pavise shield will not deter cavalry, but may be useful to soak up arrow damage (e.g. from a keep or TC) like a battering ram.
I think it’s reasonable for the French (or any other civ) to have shared traits with other civs. The kind of asymmetry in a Starcraft or AoM, where you have aliens and dwarves, does not necessarily reflect a historical RTS. Take the CoH series, where the mechanics are nearly the same, but the factions really look and feel different.
After watching the Mongol v. Abbasid Developer Showcase match, I get the sense that civs that rely on cavalry, including the French, will struggle against the Abbasid and any future camel-featuring civ.