Gazelle
G.O.A.T.
Form is such a fickle beast and something really hard to trust though, if you got the Roger form that he had when he torched Murray in the 2015 Wimbledon semi-final, or the one that torched Wawrinka in the 2015 USO semi-final, we're talking about more major victories. And that's Roger, who's very mentally tough.
Mental toughness not something I attribute to Cilic. I wouldn't call him a mental midget but I wouldn't call him a mental stalwart either. Form in these tune-up tournaments mean next to nothing.
Hell, I felt like 2014/2015 Wimbledon & 2015 USO prior to the final that Federer was playing the best tennis of anyone. Could be biased there though lol.
Really depends on how heavily you weigh form / history / external factors I guess. I've never been overly-reliant on form as it fluctuates so heavily.
Oh, but he is a mental midget. Last year alone he lost 3 matches from 2 sets up. And I remember quite a few chokes from a few years ago. He once lost against Murray after leading 6-1 5-1. Go figure.