That's an unfair argument for reasons explained above and the only reason you're picking on tanks it's because it's the most jarring difference. Both the shisui and the sky rat sets are pretty much the same (with minimal changes) for every role. Sky rat is arguably more fitting to the "leather types" of dps while shisui... is... i dunno. probably something they know players like. I mean after all it is said that school swimming costumes were what saved Tera.
I mean if tanks can't get skimpy stuff (as much as i strongly dislike the style) then how dare those healers have access to rathalos set or the wild rose set or the daystar set. *sigh* We shouldn't be petty like that.
I would like more different styles. I would like to get "sci-fi" based styles that don't have insect inspiration to them. I really liked Alexandrian gear but they always have to add a beetle? appendage that ruins the damn thing. Scaevan gear? Looks awesome but has the head of an halberd on your back for heavy armour users. Like... wth. As much as people complain about the crafted healer robe i actually like it because it has a turtle neck shirt underneath it and the embroidery bit is very pretty. I still dislike robes in general because they scale awfully on Roes.
I would like to see more gear with fur in it as well.
People complained that healer was just a recolour of the casting set so the devs switched things around and personally I ended up feeling a bit sad because there's some really cool stuff that one got that I can't use on the other anymore. Caster has the Farlander Bottoms of Casting but healers have no bottoms of that length while healer has some really nice gloves from the lvl 65 dungeon that go to MNK instead of casters.
Everything has a tradeoff.
I would also kill for some boots like Summoner boots. Seriously I just want some plain boots without any kind of florish. Sometimes keeping it simple works better.