Great feedback - and I agree especially about tanks. To piggy-back off of the idea of manipulating the battlefield, I would strongly suggest adding 'pull' and 'push' abilities to the tank's repertoire, and possibly even a damage-sharing/reducing ability modal so that you could, say, body-guard a rogue or wizard to allow them to be more aggressive.
That said, I could see them being out of control in power if such abilities weren't well balanced, especially given the amount of grenade crafting and talents available for just about anyone.
