Hardy was definitely one of the more egregious examples. He was rushed into that fight well before he was ready (ok realistically he never would have been ready but he hadn't done enough to be considered a contender at that point) and then they hyped the shit out of it. I remember things like if Serra who isn't a striker managed to land on GSP, what was gonna happen when this devastating KO artist fights GSP and only needs to touch him once to put him to sleep. People went into that fight thinking it was going to be an "edge of your seat" fight. They are still probably trying to figure out today why they shelled out $60 for it!
I am not a "the sky is falling" kind of MMA fan. But I do think the UFC has been making a mistake for some time in how it hypes fights. They are being too short-sighted. Yeah it may get you a few more PPV buys but ultimately you lose what might have been a regular customer. Think about whoever paid for DC/Cummins. I know they can't just come out and say "this card is gonna be somewhere between meh and ok". But some of the hype is basically just flat-out lying in how it sets expectations for those that don't know better. Better to have a balanced card and hype the whole thing then to oversell one aspect of it and then have all your eggs in that basket because the rest of the card is sub-standard.
The UFC put together 2 very solid co-mains and couldn't have known the other fights would be as bad as they were. But they rolled the dice on fights that had the potential to bomb instead of loading up on a card that probably had a record number of casuals and their one chance to snag many of them as future fans.