I'd hope most fans are reasonable when projecting next season's offense, and that this passed year isn't the required standard. Last year's offense was the 4th best in Kenpom, and that took Dwalt going absolutely bananas and playing like a top 15 player, nationally. Though, I think it's safe to assume we will be a very good offensive team, because JB.
We lose DJ; Simmons for Walton has to be a downgrade, if only because Walton played like a top 15 player down the stretch. But Zak was the 3rd/4th option on offense for the last 2 months, and the offense was still elite. I dont think asking CM to be the 3rd or 4th guy, behind Simmons, Mo, and maybe MAAR, is asking too much. And that's ignoring the (longshot, albeit) possibility that we pick up another grad transfer at the 4, who can take on significant offensive duties.
It's tough, though, to project little drop-off from a team that loses 3 starters and isn't just plugging in 5-stars.