I tried suggesting works implications for some character tags, but was told that because they don't have wiki entries it wasn't allowed.

Was it always required to have a wiki page for implications and aliases to be requested and I just didn't notice, or was that changed some time in the recent past?

I think that was a recent change. I also recently tried to submit a 'bulk update request' for clothing-oriented tags, but was unable to after several different error messages (including the 'lack of a wiki page' you mentioned).

It only seems to have started after the recent site update. I'm not sure if it was even an intentional change, or something that slipped in accidentally. If any mods are watching, this topic also raises the issue.