I don’t recall seeing any of the cursed Arakkoa wearing anything other than cloth, granted that was during BC when the NPC models were more limited. The uncursed Arakkoa in WoD I think may have had armor on other than cloth, though I’d have to see all the models and bosses from raids and dungeons to be able to confirm that.
Regardless, if Arakkoa were to become playable, they would get armor models of all four types of armor. I don’t see why they would be relegated to only cloth armor, and that would be rather silly if they did that while they could be non-cloth wearing classes.
For any race that becomes playable, Blizzard would likely make full models from the bottom up to be able to wear all types of armor and such. Even if they were to somehow change NPC race models into playable ones, they would still do all the work needed to flesh them out as a playable race and add what is needed in that regard.
I’m sure you could have some really neat armor that goes well on playable Arakkoa. If you’re interested in seeing more info on playable Arakkoa ideas, check out the OP’s Arakkoa megathread here:
Lots of great ideas there that could show how well Arakkoa would work as a playable race. Armor included! 