The beauty of it for Melbourne is they have a genuine second ruck and both of them can endurance run like a midfielder so there's no exposure in conceding the hit out and playing a small to hurt them around the ground.
Each of Melbourne's rucks is a genuine #1 strike ruck. Oh, yeah, TBR. Stamina to burn. And then, given the setup, they'll have 70 and 60% TOG each when it suits them.
Always fresh.
Conceding the hitout? Dangerous before 666 and stand mark rule. You'd only do it in planned phases. (Or nothing to lose phases.) It has not been sustainable for50 years of my observation.
Having got that out of the way we can probably all agree that if any side can get a VG small on either Max Gawn or Brodie Grundy at the fall the good small will win. And if a side can get an actual tall back on either of them (when forward) the tall back will win.
It remains to be seen how the setup works out over the year. Melbs has a thick and strong list, if idiosyncratic in structure. I have them clear Premiership favourite at this stage.