I'm personally not a fan how mages seem to be balanced.
I'm all fine for utility taxing some dps. But I personally feel that offensive utility should tax more than defensive/res utility.
RDM (and SMN) having a res should taxt their dps a bit but not by a lot. It should still be better to take a BLM once ur finished progging but the difference in rDPS shouldn't be big enough to make you feel bad for going RDM instead.

I also disagree with mobility being a massive tax either. At low lvl play it's going to help players a lot to have mobility but for players who are pretty decent it just feels bad.