A few notes. For Concussive Shell, I'm not sure why you want this bouncing off of enemies. I get the idea of a shell that bounces once then explodes, but if it directly hits a hero, it feels like you should be rewarded for that, or at least not have it bounce off of, and presumably away from enemies.
For Dive Bomb, it feels strange to couple a leap with an unavoidable nerf to your movement speed. Feels bad. The leap would be fine without it, I think, particularly if you can couple it with blast jumping.
Blast Charge is pretty good, I think, and I like the ultimate, too. I think this is a strong design, and a nice presentation.