We just gotta wait for Mac year 2.
Mac had a good rookie year, showed some good things - decision making, mobility in/out the pocket, accuracy, and solid intangibles, as he never looked out of it - and some flaws - arm strength was a little bad on deep throws inside the numbers, the velocity on his throws wouldn't always be consistent, he would occasionally sail passes, and he would occasionally check it down too early.
This is how I see it:
If he can somehow get this roster to playoff contention, he's the guy, and we have something special.
If we regress a little and get 8 wins only, then that means that he's "good" but one of those guys that's gonna need that special year where everything falls in line with a stacked team + special playoff run in order to win a super bowl.
If we regress badly and get 6 wins, then he's just Dak Prescott/Kirk Cousins/Baker Mayfield tier - even if you build a good team around them, you can't really trust them to beat a good team with a good QB.