I've seen too many times ends on the lighter side get swallowed up by tackles and and guards. It's harder to move a 305lb crawford off the block than a 245lb Kyle Wilber. But you're right it is about using leverage and getting off blocks. DWare was on the lighter side for a DE and was pretty Damm good against the run. He did get worn out fast though. But having that weight and using leverage is that much more of an advantage. Collins, McClain, Crawford, and Lawrence have some good speed off the snap so I think give them time and that run D should get better. Mayowa, Jack, and Irving are better rotational guys.
I worry about the lack of a thumper at linebacker though. The run D would be way better if that #55 had his head screwed on right.