These changes sound pretty good. Should make a good difference.
Though, the Siege Exo might kinda lose it's purpose with the AoE change, when I think about it... as that effect isnt much different from that of the Assault type, but he lacks the strong single-target attacks the Assault also has. I'm not sure how other players were using the Siege exo, but in my case it was sorta an emergency room-clearer, like if I opened a door and there were way too many in there. Other than that though, and maybe the Shadow Torpedoes, he seems weaker than the others, so I usually only pulled him out to launch rockets. A bit too situational.
The one other thing that does occur to me is that the Explosion Booster items really dont work on AoEs that are that small; you simply need too many of them to increase it by even one level for them to be worth it. I think the rocket launcher was the ONLY thing I'd ever used them on, for that matter. They dont work for the grenade launcher very well, that's for sure.