It's a challenge right now, for sure. Lots of legit points above. Ideally, we'd recruit some 3-4 year types and 1-2 one and done, top 5 types, each year and would then have a good mix. I think Frank Jackson is that 3 year type; so are Kennard and Grayson. If there wasn't so much upheaval this year I think all three could have been back or at least two. We still might have two come back. Or three. That gives us some vets.
The second issue is more the make-up of the actual team. After Jones left, we have not had a PG. If we don't get Duval, we won't have one for 3 straight years. This goes to the challenge of recruiting and recruiting a better make-up if possible. If K recruits a 3-4 year PF, but then, recruits over-top of him with a OAD PF, and does so 2 years in a row, then that's a mistake and it's basically a waste to recruit the 3-4 year (see Jeter).
But, then again, if you are recruiting a 30th or 50th rank player, he needs to develop. Jeter had some injuries but he just did not develop. To be honest, many of the recruits that stay at Duke do not develop a great deal from their freshman year. A few do but not enough.
Another problem may simply be that kids who go to Duke expect to become great players and be drafted in the NBA (unless they are a fan early on and want to go there regardless - like a Grayson, even though he has NBA potential).