I personally dont care if they leave GD's the way they are for PvM. But in PvP i have 89 Fire Resist on my suit and the Dragon Breath does around 80HP of damage.Breath damage from a greater dragon [wild] against 70 fire resist, does around 60 damage. The breath damage is based on the remaining hp of the dragon. The normal formula is (Base damage=HP/10).
For a greater dragon that has around 2k HP this means something like 200. Then you apply your fire resist and you should only receive 30% of that Base Damage, that is 60.
Now, considering that upon taming the hp of greater dragons is halved, the maximum damage a greater dragon [tamed] can inflict with its firebreath should be 30 against 70 fire resist. To receive 90 damage from a firebreath you should have around 10 fire resist.
I don't think there would be a problem with the GD's the way they are now in PvP if there was no guard zone for the tamer to hide in.
You see what happens is that the tamer sicks the pet on the REd, at the same time a stealth archer dismounts the red. Now the Red is dismounted, bleeding and redlined on less than 1 second.
If the GD didn't do 80+HP plus the bleed in one hit, it wouldn't be so bad. But they do.
Maybe the only way to resolve this is for the tamer to have to have the maximun skill points in real skill, without items to raise their skill.
Again I say this for PvP only, I couldn't care less about PvM.