Word of mouth is a big factor, hence why a failed gimmick like Swarm (it was advertised as an intense gimmick, a la Thirteen, and we all remember how that turned out, even if a fair few of us these days actually like Thirteen) hasn't had a decent reception...
So looking at it, it's all about how the ride is presented by the park through both real-life and promotions and whether or not people's perceptions agree with the actual ride experience...
If the ride had ended parallel to the intense connotations given by the theme and adverts, then it would probably be loved, but as the Wing-Riders are all about the experience rather than intensity (based on some reports off Gatekeeper, this theme is a constant), it didn't match up so wasn't deemed 'good'... Whilst Saw, Stealth and Colossus are pretty much clear what to expect from the ride, and do actual run parallel to these expectations (Saw runs like a death-trap, Stealth and Colossus are Ronseal rides), and are hence more successful...
So really, it's all about whether or not the gimmick fits into the ride as a whole and how the park presents it... But I'd much rather see a ride that doesn't rely on such a gimmick and just be damn good and then have that news spread through word of mouth, I dislike how every new thing in the UK has to have a gimmick or be unique or have an IP attached to them and results in a rather poorly thought out ride, it's just a pet annoyance...