The major thing that playlists need are different armor sets. Having the same armor across each activity has grown stale tbh. Especially because the changed between the sets don't feel unique enough. Or if we can't get new sets for each activity what else would be cool is if every season we got ornaments for the sets. Another thing that could help the core playlists out is adding old shaders, emblems, and ornaments into the loot pool for them. It won't make or brake the playlists but having extra rewards would be cool. Finally I would love to see them bring back Ghost shells, sparrows, and ships to either the end of activity rewards or in the rank up engrams.