I think the pve raiding game could have increased replayability factor if they added more incentives to farm current content. Seals, socketed, and warforged gear help alot, giving raiders reasons to run content on farm, even when they already have gear, in pursuit of that perfect drop (socket + warforged)
My suggestion would further diversify loot drops.
Assign a range of stats to all items, take any item and allow it to have a range of distributed stats, and remove or alter the current warforged mechanic.
Ie:
current ilvl670 railwalkers ratcheted boots
150 armor
182 agi/int
273 stam
123 mastery
118 multi
% tertiary/socket/warforged
instead ilvl670 railwalkers ratcheted boots
140-150 armor
177-185agi/int
264-276 stam
119-127mastery
114-122multi
% tertiary/socket
its not so much that it is game changing, in fact the range of values from worst to best are about the range for the current warforged mechanic, but this would add more uniqueness to every piece of gear that drops. And of course that special feeling if you get a great roll.
*many will realize the current crafted gear mechanic works like this, and its fun trying to craft that perfect roll.