interesting but i had the same result with the two corners of the gate, exactly like during bonus boss fight. this can make things easy for unexperienced players with positioning problems. the add remain an issue if not correctly treated, wall or non wall.
the heroic moment is a good idea.
This is significantly easier than most of the PuG runs I've had to heal on my server. For organized groups this is mostly worthless (you should be downing it easily anyway), but I'd love to see this more widespread among people who stand on the edge and get knocked off, or otherwise make the fight harder than it needs to be (not picking up dogs for example.)
The heroic moment thing is quite awesome, for so many reasons. I am almost 100% sure it's unintended but it also works in Cad with the dog you can release there with Bioanalysis...