Why aren't there more tanks in FFXIV?

[Granyala]

I don't usually have an issue to hold heal aggro unless the person over-heals me or if he/she suddenly lands me a bigger heal while OP is out of my rotation (thus, the secondaries may run to the healer if the aggro on me is too low). I usually pull them back quickly if that happens though.
Heal aggro is something I DO account for and I can go out of my way to keep the healer alive and well.

What I don't care about is the people that do crap and do nothing to improve, and the types that when you give honest advice only throw vitriol back at you.

Yeah it's important to hold your horses as a healer on pull and esp when adds appear. To be fair: I mostly aggro in low level content so while annoying I never say anything, b/c I assume they are still learning.

As for the second part: In WoW I tank like this: Whomever finds the aggro of incorrect targets gets to keep it. (Healers excluded, but they can't aggro in WoW anyway)

[Granyala]

(healers don't count, they get aggro just from existing...)

HoT on pull... instant aggro, just add mob.