I mean, admittedly I need to add some kind of gallery where you can see the ones you've collected (basically a CS-Dex)
yes please, that would actually be amazing.
My issue with this would be that for completionists who like to have full living dexes, adding a CS Dex of pokemon that cannot be obtained anymore without trading would make it impossible for some people to complete theirs as people would be very hesitant to trade something like that.It could be argued that this is already a problem for some considering they‘re in the game, but that problem would only further itself if they were put in the/a dex
It could also give reason for Niet to do events to bring them back. Currently, they're so under valued that when he last tried to do an event that gave away the AZ Floette(?) no one really bothered with it.
If Niet made a CS dex, even if it doesn't add to the actual dex itself, he may finally be able to have people interested in those types of events.
Just because he said they may not come back, doesn't mean they wont.