I think Mayfield is better than he showed last year. But the fact remains that he's limited. He's got an average arm, average mobility (in a league that really, really rewards mobile / running QBs), and doesn't handle pass rush pressure well. Those flaws are baked (Baked?) into the cake with him, and permanently cap his upside in the lower half of starting QBs.
I'd take him as a bridge quarterback 50 times out of 10 over Carson Wentz though... don't know what the hell Washington is doing there. Baker will eventually settle into that kind of Carson Wentz, Teddy Bridgewater type role as a 1 year gun-for-hire. He's not a franchise QB in the league, but he's plainly smarter and more accurate than a lot of other QBs, and that will keep him cashing checks for a long time.