To me, standing outside Telestra's room with your ranged DPS is "creative use of game mechanics", not "avoiding game mechanics".

This is because even outside the room you get thrown up in the air, you can't cast anything except instant spells, etc. The only difference is you don't get throw around, just "up". It doesn't defy any sort of weird laws. You're being thrown into a wall over and over again, the same thing that would happen in real life if someone tried to "pull you" towards them and there was a wall in front of you. For multiboxers, it just makes things easier because we don't have to reposition afterwards.

Although now I'm pretty sure I could own telestra just using 4x healing stream totems, but this is certainly a good tactic for starters.

Edit: More than likely blizzard will change this in the future anyway, to make the invisible barrier block spells, not just movement, then you won't be able to stand behind it anyway.