Was thinking about my D3 team, which blocks a lot of shots, but doesn't get many steal. A steal seems like its a better defensive outcome than a blocked shot, since a steal is 100% going to terminate a possession and give your team the ball. A block can be rebounded by the blocked team and as such isn't 100%.
In real life, a player who blocks a lot of shots also changes shots at the rim. So in HD, if you have a player with a high BLK rating, even if he doesn't block the shot, he SHOULD be able to reduce the chance that the attempt in the paint is successful.
If not, I'm going to have to start playing small-ball.