Both are very exciting and talented fighters but I wouldn't exactly say I am a fan of either... Ugh... Part of me wants to say Rockhold but him training with Hooft gives me pause. Maybe that will be a good match as Rockholds biggest weakness is his hands but I can't recall the last fighter whose done well in a high pressure matchup under Hooft. As a coach the man seems to give decent technical insight but overall bad prep and psychological management.
Yoel is 40 years old and I tend to think the likelyness of him hitting a physical decline is going up precipitously at this point. In terms of style he reminds me a bit of a more dynamic and skillful Woodley, in the sense that he's low output/high damage. His wrestling credentials are impressive though he did get taken down against Weidman (got right back up though) but Rockhold's also a great ground fighter. So that's kind of a wash. Rockhold maybe able to keep Yoel at bay with his great kicking game but that's a dangerous play against a guy with Yoel's power and creativity.
I think the Rockholds glass chin/Yoel's 5 dollar gas tank argument is a little overplayed but there is merit to that dynamic when considering the matchup.
If a gun was put to my head I'd probably say Yoel Romero, but if I was putting money down I'd go with Rockhold.