Forgotten is definitely worse. Luvdisc and Delibird are at least memetically known for being absolute rubbish, so much that we write joke analyses of them (which are btw really entertaining to read), and Ledian is at least known for its great design ruined by terrible stats. With that have they at least made some mark upon the mind of the playerbase. They at least have some sort of appeal, and part of it is the very fact of being a shitmon. They incite the kind of fascination, that we get out of reading The Eye of Argon or watching Ed Wood movies. On the other hand, how much do you even hear Wormadam, Lumineon and Stantler getting half a mention, that is outside of "Pokémon you didn't remember existed" threads? They make it into that kind of category, because they're only bad, not spectacularly bad, or they're bad and don't have any other kind of appeal to the fanbase, such as design. That is a worse punishment than being an absolute joke imo, being forgotten as Pokédex-filler at best. At least Delibird gets some attention.