People way overstate how Fitz looked IMO. He looked better than Tua at times, but Fitz also plays with an insane amount of DGAF. That helps a lot when your top WRs are an injured DVP (who has always been a guy who plays terribly through injuries, if he plays), Isaiah Ford, and Jakeem Grant. Those guys don't get separation. Fitz would sling it to them anyway. It works well in the short term, but we've seen enough of the beautiful fitzmagic show to know that eventually it blows up in the teams face. I'm pretty confident Herbert would also have struggled compared to Fitz in that situation.