Being able to pitch a ton of well above average innings is extremely valuable. Carlton was better than Hunter. It's not tough to see.
Cartlon threw 5,217 innings
Hunter threw 3,449.
Carlton had an ERA of 3.22
Hunter had an ERA of 3.26
Carlton had an ERA + of 115
Hunter had an ERA+ of 105
Carlton struck out 4136
Hunter struck out 2012
Carlton had a FIP (fielding independent pitching, scaled to ERA) of 3.15
Hunter had a FIP of 3.66
Carlton BB/9 3.16
Hunter BB/9 2.49
Carlton HR/9 0.71
Hunter HR/9 0.98
The innings and strikeouts alone put Carlton way over Hunter. Innings are valuable. Realistically, a pitcher can only control a few things: his K rate, his walk rate, and his HR rate. Hunter has the edge in the walks but Carlton's lead in innings and strikeouts are so much larger that BB/9 rate difference isn't enough to sway anything in Hunter's favor.
Carlton was significantly better.