Not surprised in the least - I called it long before the draft. I never saw any signs of him having the skills / talents / attitude to be anything but a glorified defensive role player and energy guy.
The way I see it he projects to fall somewhere between Trevor Ariza (if he ever develops a quality jumper) and Michael-Kid Gilchrist (if he doesn't). Ariza is a nice player and most teams would love to have a guy like him as a piece, but he's not exactly the type of talent you hope for from a top 5 pick. In the 6-12 range you'd be pretty happy.
Right now Jackson's only stand-out talents are his athleticism and his perimeter defence - anything beyond that he is gong to have to develop from scratch, and with his current level of ego / arrogance he doesn't strike me as the type who would be coachable enough to make those kinds of strides.