While its true that if Svi lives up to his current 2016 NBA draft projection it will be huge... I still don't think he is the biggest key to title for this year's team. After a lot of thought, I've come to the conclusion that the key is.... (drumroll please...)... Carlton Bragg.
My guess is that the starters will be Mason, Graham, Selden, Ellis, and Diallo. The starting lineup is solid. One can reasonably assume that each returning player will have gotten slightly better than the previous year. It doesn't always work that way but for simple analysis, the likelihood is that there will be at most one player that does not improve, gets injured, or regresses from last year. IMO, the key to being a championship contender is having someone (or more than one) take a big leap forward in comparison to last year. That's what would make this team dangerous. Many think it will be Svi. But if its not, and someone else does instead, this team will be equally as dangerous. With the depth of the backcourt, the need for it to be a backcourt player isn't critical. In addition, there are many alternatives to Svi taking the leap forward. It could be Mason (early reports saying he looks outstanding), could be Graham (made 7 threes in the scrimmage the other day), could be Selden (he's due for it, he has all the tools, just needs to put them together), could even consider Greene or Vick as longshots as well. That's 6 guys in our backcourt with the chance to be the difference maker which makes the need for it to be Svi not as great. There are other options.
The frontcourt is a different story though, the depth is not as great. Perry has been KU's workhorse and I'm assuming Diallo will be a solid compliment to Perry in the lineup (not a guarantee though). Off the bench we have Traylor, Lucas, Mick, and Bragg which at first glance appears mostly to just be stop-gap or specialty players. Traylor plays well at the top of the key where he can drive to the hoop or dish it but has a weak outside shot. Lucas is strong on the boards and has some success close to the hoop but no outside shot either. Mick hasn't been able to crack the lineup over Traylor or Lucas and I'm assuming is a long shot at being the key next year. Bragg as a frosh is expected to be a serviceable backup with upside. What concerns me most about next year's team is the dropoff when Perry or Diallo gets in foul trouble or heaven forbid, gets injured. It seems that over the course of history, players who make big jumps in their skillset in a year tend to do it in one of their first three years. Can't think of too many seniors (or 4th year players) that come out of nowhere and end up playing way above their projection. If this non-scientific trend is true and continues for this year's frontcourt, that leaves Bragg as the only candidate to be that guy. The lack of skilled depth in the frontcourt is why I think Bragg is the biggest key on next year's team.
Bragg has a nice jump shot, short clips from practice have shown he has some good ball skills too. I think the cards are in his favor on this one. He's a five star athlete has the tools to be the guy. I'm calling it now, if KU makes a run to the title game next year, Bragg will be a big part of it. He is the key.