^ Agreed, it was clear that by Insurrection they were just kinda, "Hey, just put Worf in there, nobody will care why" about it anyway.
(IMO it wouldn't even be an issue if
they hadn't costumed Worf in a Starfleet uniform. It'd have been completely acceptable for Worf to just be there for Riker and Troi's wedding, but then happen to still be around when the Shinzon situation rears up, and he offers his services accordingly (but remains a civilian). His role in the script could therefore remain the same without it bothering the continuity of how he left DS9.)