Would it be possible to add previous mission pass season cosmetics to the mission badge shop? Mission pass cosmetics are already non-tradeable and mission badges themselves are a kind of limited currency.

I don't really see any reason other than artificial item exclusivity to not be able to buy previous (emphasis, untradeable) cosmetics with your badges. Not to mention that the mission badge shop hasn't been updated at all ever since the beginning AFAIK. Thoughts?

I agree that they should add this feature, and this is coming from someone who has all the items from all the Mission Passes since Season 1. I've actually made a similar suggestion myself, in which they should make a shop with all the past items, and price each item for 1 Mission Badge each, as that is how they value them when passing up on them in the Mission Pass. It would also help with the cosmetics storage issue, as them being 1 Badge each, means that they can be returned to the shop for the same price.