Despite the fact that he uses gimmicks, we all have every reason to believe that DB is a very skilled cardician, simply by the things he does with cards in his specials (most notably "Street Magic"). As melb stated, Blaine's execution of the hot shot cut and Instant Replay (and the Simple Switch, for that matter) are entertaining and impressive, not to mention flawless. I've especially gained tons of respect for his execution of the Simple Switch as I personally took months to learn it and am familiar with what it takes to pull off this almost impossible card flourish. In addition, his double lifts are also executed very nicely. Top change, Immediate Bottom Placement/Convincing Control, classic force, shapeshifter, snap change, etc. He does all of these things well. And in the opening montage of "Street Magic" he does a nice thumb fan (with the one handed closing technique) and there's a brief glimpse of him doing the one handed riffle shuffle (a flourish that I currently cannot do to save my life). It's all of these little things (and not so little things) that impress me and prove that DB has the skills.
This is precisely why I absolutely love "Street Magic" and how every DB special after the first one did not entertain me as much. I would love to see him do another special with the quality and simplicity of "Street Magic", but alas that will probably never happen as with each subsequent special, his tricks get more and more extravagant, complicated, and less to do with cards (not to mention few and far between). Regardless, I anxiously wait for the emergence of Blaine from his 44 day public fasting just as his next special hits the airwaves (should be around mid october).