People wanting to take the time to do it is irrelevant. I may WANT to join ToT LFR on my fresh 90, but the game forces me to get more gear. So I go and afk my way through H Dungeons, MV / HoF / ToeS LFR, and can finally que for ToT LFR and I don't even have a keybind. "SWEET! you mean I can /dance the whole time and you'll gimme pretty purple pixel lootz!!!"
No. Just... No. You should be able to show that you know your class. The time it will take to clear bronze and silver Proving Grounds will be a drop in the bucket when compared to reaching the ALREADY REQUIRED ilvl. Maybe award a piece of loot to make up for the lost time you coulda spent gearing? (trust me, not normal mode loot, just a little token of appreciation)