Agreed with the OP, GLD tanking gets a fair bit easier at the higher levels. Getting Shield Oath as Paladin is amazing! Makes such a difference.

The most frustrating thing I find in pugs is people using abilities while I'm pulling stuff from a distance. So I'll mark a patrol, shield lob/provoke it from a distance to draw it back and before it even reaches my melee range someone will start attacking it or casting abilities. When you do lose a mob it's also pretty frustrating to pull it back with the abilities you have in this game. If something aggros you don't just continue to attack it, wait till the tank pulls it back...otherwise you're basically having an aggro race with the tank who'll have to run over to you so he can melee the mob off you which is just a positioning nightmare.

and yeah, healing seems to generate so much aggro in this game. I've experienced the medica spammers...