I would hate to see Krstic re-signed and take all of Stiemsma's minutes.
The big man rotation, outside of Garnett, would be so weak defensively.
Another weak rebounder too.
Don't let Krstic's poor performance with the C's fool you. He does have a high skillset for a big. I would give him a pass as he dealt with a mid-season trade, a new system, and a significant injury he was playing through. He's only 2 years older than Steimsma. Let's not forget that.
Different players, but Krstic is by far an upgrade over Stiemsma. Maybe not on the defensive side of the ball, but overall, Krstic is flat out better.
The 2nd unit would be setup quite nicely. Krstic can score, Sullinger can rebound, with Green & Terry playing their roles. Extremely good bench, especially if Sullinger pans out. Good options for Doc to run with.
Both Krstic & Wilcox provide safety nets in case Sullinger & Melo aren't ready for the jump. If Ainge hits on one of those rooks early, watch out. Scary team if that's the case.