Blake is an amazing athlete, way better than Duncan ever was. However when you're talking about the game of basketball Duncan is clearly the better player. Duncan came into the league ready to go, and has set milestones all throughout his career and continues to do so. Blake is personally a favorite of mine because of how athletic he is, but his game has waaaaaaaay too much that could use improvement. Also think about this, Blake is an ok defender at best, Duncan till today is a force defensively. There's really just no comparison.
Go Timmy Go!