It really has little to do with other people get. Its more about my own experience with getting gear not really suited for the content i play.
Lets imagine, that i am the only person in the world who gets TF. Then we remove the possibility of butthurt over other peoples gear. I go into normal raid, i get TF, suddenly i have a head piece, which is heroic tier, if not better.
I clear normal raid content and end up getting about 4 pieces of TF with heroic quality or better.(Im not a speedy raider)
I go into heroic difficulty and from the very start, 4 gear slots of gear is already useless. If a boss drops a helment with TF, its now suddenly useless.
So i went from one difficulty to another, and suddenly the chance for rewards is now lower instead of having been reset.
TF makes it so that jumping from difficulty to difficulty becomes less and less rewarding, as you over time get TF pieces, that are just better than what you will get in the future. The entire idea about jumping from normal to Heroic(or heroic to mythic), is that you are resetting your supply, making all drops valid again. TF creates a situation, where instead of being 100% rewarded for increasing your own difficulty, you might end up with tossing away 50% of the gear you get from killing new bosses.
So again, it really has nothing to with other people having better gear or anything. It is all about messing up the gear ladder experience set up by the difficulty system.