Luis Ortiz because he is more a natural heavyweight. I think that prime Luis Ortiz was largely avoided, just like Povetkin. I also think that a prime Ortiz would have beaten Joshua/Wilder, whereas Mairis Briedis was never at that level in HW. Even if prime Mairis Briedis with Gassiev and Usyk, is probably the most dangerous Cruiserweight since 2000's by far.