Personally speaking, I would love to see more permanent cosmetic items. I've bought pretty much every cosmetic that I like (from the ones I can get) but there's older desirable items that seem to be gated off for now, like the Blaze Hawk gear.
I get that it's nice to show people how OG you are by what gear you have but for newer players it feels like options are quite limited in contrast to the plethora of options there have been historically.
Perhaps there could be gear which is unique to a season but then is remodelled slightly and added to the store permanently? That way older players could still show their longevity through the original items but newer players have more options in the form of the tweaked items. The viable part is that if these are only minor tweaks to the overall model then it's not an expensive job for PHXL in terms of resources.
Yeah - as we get Event Passes off the ground and figure out where they sit cost wise and timing wise, you'll start to see more returns of past content. There is always the vault as well, but that has some issues to iron out for sure (hard to know what's coming, what could come, or what was in there before)