They won't be markedly better than they were this year.
Cluff is a good positional post defender... but he doesn't guard the perimeter well, and he isn't a rim protector. Cluff is also a very good post offensive player, but he's similar to TKR...and neither of them are going to help spread defenses out...and neither are dominant enough, like Edey was, to create gravity that will pull defenders away from Loyer, Smith, Cox, Harris... You're obviously not going to just add Cluff's numbers and impact, on top of what TKR became last year. Together they averaged like 40 and 20 last year... I'll bet a lot of money they don't average that, combined, next year. Cluff will help with rebounding...yes. But losing Heide and Colvin, will hurt the rebounding. Probably a net improvement anyways, I'd say...but losing those two athletic wings will have an impact on rebounding efforts.
Colvin and Heide, were long, athletic, wings. Their departure leaves Purdue with exactly zero long, athletic wings. You know, the types of guys all Final Four teams (that don't rely on anomalous big men like Edey), have a handful of.
They're settling back in to being Purdue... I think that's great. It'll provide very good competition for the B10, and IU...but there will be basically zero threat of them hanging a banner.