Every single person with knowledge of catcher defense and the Red Sox would say Swihart is worse on defense and game calling than Leon & Vaz. I'm sure of this.
Now, you are back to saying Swihart has more "pop" and "slugging", when there is no evidence to support your claim... even ST'ing numbers show Leon is at least equal.
Again, I'm all for trying to find ABs for Swihart. That's one reason I hated the Moreland signing (not the major one). I want Swihart to make the 25 man roster, and he'll get a chance to earn more and more playing time by showing he can one, hit better than others and two field any position he is asked to field at a decent level.
I do think he should hit better than Leon this year and probably better than Vaz as well, but I think you vastly under estimate the value of catcher defense, and or you vastly over rate Swiharts catcher defense. Yes, he can throw guys out well enough. To me, and many others, that's just a small fraction of the value of catcher defense.
Swihart is already old enough to have shown significant growth in this area. Can he get better? Of course, he can. VTek wasn't really a great defensive catcher until his early 30's.
We are not going to hand Swihart a big chunk of starting duties in hopes he learns as he goes. We're already doing that at 3B and have serious defensive issues at 2B and SS (and 1B with HRam). Swihart's best chaance at getting ABs is at 1B or through injury. He can PH a lot, and show he can hit, and then he may get more and more ABs. Even then (assuming an .850 OPS), I doubt they make him the 1 or 2 catcher.