Personally I would say they're both equally adept DMs, but I'd play Besic deeper because I think he's got a better range of passing, and McCarthy is more box-to-box. But your reason makes sense, too.
This is all academic of course, because Gaz Baz exists.
Yeah at DM theres not a great deal of difference, McCarthy probably just shades it with a slightly higher level of erm, level headedness, but both can tackle well, shield, track runners and both have bags of energy.
Lets hope they both play lots next season, people who know football can see the talent McCarthy has in his role, hopefully Besic will silence his doubters.
But yeah, Gaz Baz, not as bad as most make out IMO, still got a part to play in our future.