I think werewolves have kind of earned their place in mythology not to seem intrinsically naff. Any other x-thropes haven't quite got that historical weight behind them, and seem naff as a result, particularly given the internet's attitude toward furries. Everybody knows a werewolf, but a 'novel' concept involving another animal will be approached as something new, and through that rough spectrum of 'How much is this furry?'.

Pretty much every defined 'supernatural/horror race' is intrinsically naff in its purest forms, but werewolves have a long-established lore to draw on. Part of the charm, for me, at least, of watching supernatural/horror-race-themed media is to see how they will interpret the lore and what new spin you'll give on it. If it's not an established 'thing', though, there's no room for any of that comparison, which makes the new thing seem more alien and less approachable. The audience doesn't buy into it; it's considered naff. 

Werewolves, incidentally, have a long history in Western cultural awareness, from being the antagonist in Biblical parables, fairy tales and even aphorisms, which lends them to the villainous, or, at least, dangerous role in a given story. I'm not sure big cats have that lingering cultural or folkloric heritage.