Searched a bit, didn't find anything like this.
My idea for Tier gear.
T11 should be obtained through raiding the appropriate content and turning in a token drop (we've seen this).
T12 should be obtained through raiding the appropriate content and turning in a token drop along with the previous tier's counterpart (new).
If they follow this model, you can only obtain Tier gear via raiding, and by raiding each step of the way.
You can't have T13 Shoulders if you don't have T12 Shoulders, which you cannot get until you have T11 Shoulders.
Now I know what some of you are thinking.
"You're nuts! I don't want to have to run old content! QQ plox and the like!" Whatever you crazy kids say nowadays.
But by running current content, regardless of what Tier we are currently on, you can obtain off-set pieces via boss drops.
It will just be the Tier gear that's limited to this gating system.
since you can only run each raid once per week (no 10 + 25 runs), you can gear up your alts to get the Tier gear while it's current.
I know, it sounds crazy and anti-friendly, but I feel Tier gear should be special and reserved only for raiders, not just the 5-man runners who are one tier behind.