Bad news is no, there is not a single fix. Good news is that while there are multiple issues they can all be addressed with the current personnel. Dial back the Final Four talk but this is still a team that can win 20 - 22 games including enough signature wins in conference to get to the dance and have a realistic shot at being a Sweet Sixteen team.
I. Interior defense - Terrible so far but a number of options for improvement. DC knows the zone, generally plays position D well and has the physical stature and strength to body with bigger post players. He is not a consummate rim protector or shot blocker and doesn't react particularly well to the wings but he can be a solid presence. TT has the athleticism and length to be a plus defender in the middle. While he could use more bulk, I think he could make up for it with quickness. At this point, though, he is lost in the middle. Needs to learn how to defend the high post without giving up the low and how to rotate effectively laterally to help out on baseline extended. Worst case, Lydon can give us effective minutes in the middle. Proved it last year and while not ideal he provides at least a competent stop gap.
II. Rebounding - Stunning how poorly we have performed in this area. Individually this should be a strength of this team. Coleman and Roberson can rebound with anyone. They need to be on the court with more regularity but they need to produce when they are out there. Chicken - egg thing I guess. Thompson and Lydon have the size and quickness to be very effective at both ends of the court. White, Battle and Howard bring size to the backcourt and White, particularly has shown the ability to be a strong rebounder. Yes, I know that the zone makes it more difficult to seal and block out but to me effective rebounding is an effort and focus driven activity and it is sorely lacking up until now.
III. Cohesion on offense - Toughest to address but the optimist will say this is a function of so many new pieces struggling to work together. Half court seemed to be settling for the three too much early on. There looks to be more of a focus on driving to the hoop in recent games, but Gillon is the best at this and can't finish, Frank is woefully inconsistent and Battle hasn't really taken up the mantle yet. Will be interesting to see if he is given an opportunity to run the offense in the next few games. Remember he was originally recruited as a one. Let's see what he can do. The biggest disappointment has been the transition game. Team was advertised as a throwback to the open court running style that personified Cuse hoops in the late 80s and 90s. Opportunities have been limited by poor defense and rebounding but in the rare cases we get out in the open court there is virtually no ball movement. One guy driving to the basket. Noticed in recent games that in dead ball situations there is almost no interaction between players on the court. Chemistry is an abstract concept and often overrated but this seems to be a textbook case of how its absence can kill a team. Winning helps, playing well helps and I think this is something that can snowball. Time will tell.