Bring back old skins!
They’ve done it a few times in the past and I’m sure they’ll do it again at some point, its just a matter of when. Could be any time, really. The last time was in March, when they had a different Gem Store item on sale each day, including bringing back some of the old discontinued ones.
Grenth Hood in particular probably won’t be back until Wintersday though, since its a wintersday-themed item.
I’ve mentioned it elsewhere, but I really want those bunny ears.