Smart.
Personally, I don't believe that Randle has 20 PPG potential at all. I think his offensive skill set is far too limited, given that he basically has no offensive game outside of 5 feet. At the same time he's got average (at best) size for an NBA PF, so I don't see him dominating against NBA Power Forwards in the paint either. I can see him having the occasional huge games when he has a mismatch against 'small ball' lineups (guys like Thad Young, who will struggle to contain his physical strength) but I can't see him doing that on anything resembling a nightly basis. I can see him being maybe an 18/9 guy maybe, at a squeeze. On the defensive end he's pretty bad, and will likely always be a liability.
Smart has All-Defensive First Team potential (he's already almost there) and while his offense has yet to develop, I'm pretty confident it will come. I doubt Smart will ever be an elite offensive talent, but I can see him being a productive offensive player. I think overall numbers of around 15 / 4 / 6 are realistic.
If I had to choose between:
1) A 15/4/6 guard with All-Defensive Team credentials or
2) A 18/9 forward who is a defensive liability and doesn't stretch the floor
I'd go with the first one.