Plate idea got scrapped for basically that reason. But he does wear canvas and some guards because sometimes Aura won't save you when there's a dozen Grimm on your back. The quarter-inch might not be much, but it's better than a freaking combat skirt. 

And yes, you're probably right that he'll need a bit more mobility. I am currently working on this due to the revelation of what he's like. 

I may go back to the 220 because while that was not necessarily what I originally hoped for, it may have been the best level.