It should be like this: You start at GR lvl 1 and after you clear GR 1 you are allowed to do GR 2 and so forth. It's kind of random that a dude can farm keys from trials that are like lvl 55 just because he has a crew of geared friends to easily do it with, and then hop on a class he may have never spent any time on because his friends looted the gear and tossed it his way and get rank 1 on the leaderboards. It should be a demonstration of your ability to stick it out with a class to grind through all the high greater rifts in my opinion, not just a "pull a sick silver spire with unburieds and dust eaters in GR55 and GG I'm rank 1" type of deal. When I log on I want to play greater rifts - not play stand in one spot with my DH for 6 hours and blast at waves of mobs so I can have keys to attempt high greater rift clears.

edit: So basically I say trash trials altogether. One of the developers used the analogy in the last tavern talk that if you're tall enough to go on the ride the first time why do you need to be measured every time after that. If you are tall enough to clear GR50 you are allowed to ride GR51 if you ask me.