It may have been that I misread about RA but nonetheless changes that most likely we will be sitting on more gauge than we need to spend, and I mean sheltron mitigates more dmg and is more frequent to use than RI, so don't see there being a problem. And tbh, I genuinely feel you're overreacting to the nerf on cover, which was too broken in it's current iteration.
Tank stance significantly increase enmity so there should be no issue losing aggro so long as you actually press your AoE buttons in the right order.