A lot of people the past couple years have compared him to Dennis Johnson, and if he pretty much just stays at his current level for a decade, that looks like a really good comp.
DJ was a very, very good offensive player though. He made four straight AS games by age 27, was both All-NBA 1st and All-Defense 1st in the same year, and had two straight top-10 MVP finishes.
If Smart stays at this current level there is no way he will do that.
It's tough to completely compare the two, of course, because there was no 3-point shot when he started his career, and it certainly wasn't a huge part of NBA offenses during most of his career. That said, he never became a remotely good 3-point shooter, finishing with a career rate of 17%, which would even embarrass Marcus.
If you just compare their 2-point shooting tho, it's not far off.
DJAge 23: 2FG% 41.7%, TS% 48.6%, FT 73.2%, Per-36 Pts 16.8, Asts 3.7
Age 24: 2FG% 43.4%, TS% 49.5%, FT 78.1%, Per-36 Pts 16.8, Asts 3.7 (All-Star)
SmartAge 22: 2FG% 42.0%, TS% 48.6%, FT 81.2%, Per-36 Pts 12.5, Asts 5.5
So we see the following -- DJ was approximately the same offensively at age 23 and age 24, even tho he was an All-Star in the second of those two years. We also see that Smart is pretty much right with him -- the shooting percentages are comparable, and while DJ made about two more baskets per 36, Smart got about two more assists, so the total offensive contribution and efficiency is comparable. (And to defend per-36 for a moment -- DJ played 27 and 34 minutes per game the two seasons, and had essentially identical per-36 numbers despite the minutes increase. Meanwhile, Smart averaged 30 minutes per game, right in between DJs two totals, so per-36 is a great normalizing tool.)
Smart's biggest problem is that he plays in this era, and not the early 80s, and the 3-point shot is now an important part of the repertoire of centers, much less PGs. But I would argue that offensively, DJ and Smart are very similar. And defensively, I think it's ridiculous Smart hasn't been named All-Defense.