For the sake of some of the ornaments - I've bought every season pass but for the first two seasons I didnt complete them fully due to personal reasons. My idea is as follows....
Say I got to level 130 in the current battle pass - I would be able to use those extra 30 levels on say Season of the Undying to unlock the old rewards that I missed. I just think it would be nice, even if its only for the old armor ornaments.
Edit 1: It's a shame to see this blow up and then die off, but here is another proposed idea.
Since Ada-1 is now the cosmetic vendor, what if past ornaments rotated in her inventory that we could purchase for a loom?