On the Knock back discussion, it isn't, in some cases, just inconvenient. A lot of Tanks defense is based on the number of opponents in melee range, if they keep getting pushed away, the defense drops, sometimes tragically if you are dealing with Enemies who have ranged attacks and are still Taunted ( They Hate your Guts ) but out of melee range. You can manage this by working, if you can, use the Knock back to push them toward the Tank instead of out of melee.
A Blaster called El Jugador ( Player in Spanish ) from our Supergroup on Virtue was energy blast. He would send them flying into walls, trees, cars, mailboxes, shelving, Jay Leno, crates, stairwells, platypuses, KFC, other enemies....anything really, as long as it was near me. This was an extra bit of work on his part, but very appreciated.