I struggle to think of an otherwise good game they have "destroyed" by "forcing" a narrative or token characters.

That is to say, I don't think I can point to a case where the game would have been otherwise good. Adding badly written characters to bad games does make them if anything marginally better (at least they're consistent 😅), plus unless the devs completely lost control of their own project the consultation company would not actually implement the characters. They'd give you background stories, profiles, example interaction scenes where they took scenes and re-did them with their characters, or example lists of character archetypes to utilize this profile in.

The actual (bad) writing, (bad) characters and (bad) narrative are still up to the devs to (badly) add.

(edit)
I mean just going by their official project list, I can only personally mark out Suicide Squad, BattleShapers and Sable as bad, and none of these games needed their inclusionism - such as it is, you could argue Suicide Squad makes a mockery of it anyways - to be terrible games, they were plenty able of being that on their own. Plus again, it's the devs doing that, not the consulting company.