You must be new or a non-raider. Let me elaborate on what the real issue is and has been:

Back in the Pre-expansion days of running Molten Core and AQ40 and such, you could at a glance instantly tell how progressed a guild and a player happened to be from what they were wearing. Everything was VERY unique to the point that it was blindingly obvious (and very cool) to see certain people with different gear. It was a status symbol somewhat, and a visual inspection on another level.

Now, you can't tell by looking at someone if they're a heroic 5-man player, a 10-man player or a 25-man heroic guy because the gear looks the same no matter what level you get it from unless it's a weapon. A T7 hunter and a T7.5 hunter are going to mostly look identical. It takes away a little of the achievement of doing 25-man content over 10-man content since the stats on the gear aren't THAT much better (and speaking as a T7 hunter with a single piece of T7.5 I can say that my DPS is as good or better than most hunters doing 25-mans). At least if you're not going to be doing much more in the way of quality, you could look better while doing it or at least different.

It's probably not a big deal, but it meant something a few years ago and it's essentially meaningless now when random pieces look like tier pieces.

If the only way to get armor sets to not look mismatched and stupid (and I personally think that non-tier pieces of tier slots shouldn't match tier gear) is this homogenization, it's pretty disappointing.