Not to be a dick or anything but learn to use your aggro drop, you are going to need it when you have 7K HPS at end-game. I can't remember the last time I, on DD or healer, didnt use my aggro drop on pretty much every CD during group content.
7K HPS would be 3.5K TPS, which means a tank only needs to generate 2.7K to keep aggro off you assuming you are staying at range. If your tank can't manage at least 2.7K TPS, they need to work on their rotation. Outside of a couple of very specific situations, healer threat drops should be completely unnecessary at end game.