Just adding my take on this boss with a x5 hunter team.

This boss is hardly ever a problem if you have at least medium to high dps. If you take Dresaron down fast enough he will often start doing the push back, delaying the first / upcoming falling rocks. Also if we are lucky the falling rocks seem to have the chance to target the location of any of your pets instead of a character, nullifying that occurrence.
Even if you are not lucky and have them spawn on the team, a hunter team should have no problem to quickly disengage, or already be moving when it comes.
And we have the self heal / Shell to recover if the hp starts dropping.

In the case where your pets step on some eggs and spawn dragons, just be quick with firing a multishot to make your pets cleave and at least aggro them. If they reach the hunters before you get it off just Feign.

The push back and staying out of breath is no problem for the hunter team, since it's very mobile and moving doesn't even affect dps output.