I mean, I obviously take Smart right now.
For me, the question is this - "Is Randle any better than what prime Sully *could* be?"
Obviously, this is a loaded question right now due to the context of Sully's conditioning and place on this team. However, I don't think that Randle would be much, if any, better than Sully if they both reached their full potential. For example, I think both of their skills in scoring inside and rebounding are pretty much a wash. And though Randle is more athletic than Sully, I think Sully has a higher BBIQ and is a better shooter than Randle, or at least has shown potential to be a capable mid-range and outside shooter.
Ultimately, the question is if Sully will ever reach his full potential due to his conditioning and attitude issues. I have my doubts right now, but I honestly don't think that Randle's ultimate ceiling is much higher than Sully's ceiling.