I've always been a big fan of the grand company Elite gear sets. Even though some are nicer than others, I think it's really cool that they had their own unique sets. However, they don't really seem to know what to do with GC stuff anymore so I was thinking if they expanded your options of "GCs" that would function the same, but offer their own sets.
Something like
Ishgard- Classic crusader/inquisitor type sets
Sekiseigumi- Traditional Samurai stuff
Those Garlean separatists we helped- obviously garlean gear

And others, I'm sure.