You think he's a better defensive player than lamb was? 4 games into his sophomore year, 2 against really bad local teams, compares to an entire season as "the guy" in the old Big East? I think people forget how special Lamb was too.
You're talking about two different things. Lamb was a stud college player, but his skillset means his NBA ceiling is going to be limited. Bouknight has the skills to do whatever he wants at the NBA level. Hit the 3, beat defenders off the bounce, finish inside, get to the line (and make the FTs), rebound, and he's got great BBIQ which means he's able to make his teammates better.
You can argue that Lamb's two years were better than what Bouk has accomplished so far, but honestly it makes much more sense to wait until the end of the season to make those comparisons. If you want to now though, I'll submit that while Lamb had a great season in the old Big East, he never put up 40 in a game, let alone against a top 10 team.