FrogReaver
The most respectful and polite poster ever
Because you are to hard to hit and you can't react anymkre.
And the reasons for why not still hit the tank:
1. Focus fire on tank might still be better due to other enemies may can only reach tank with their attacks.
2. Tank ally may be out of move range.
3. Any kind of actual roleplay for the enemies may also keep them on you. (Running to the squishy may mean the enemy does more damage but may also mean he becomes primary target and will be the first to die. Then there’s taunting, basic warrior idea to prove he’s the superior warrior, etc).
In short running to the squishy isn’t a clearly better tactic, it’s not something an enemy should clearly be doing. Etc.
I would prefer heavy armor mastery. Especially since I prefer str on melee characters.
But if you are dex based, like melored's tanky ranger, defensive duellist is top.
I agree here. Though I think ac is better than damage reduction from heavy armor master, but your primary stat consideration is even more important IMO.