I'm admittedly going on the assumption they'll make Harlequins like they used to be: Not that many of them, don't like getting hit, but hard to hit and they can beat the snot out of people fast.
I hope they go in that direction. Means they'll be kind of nasty with power gamers, not so great with newbies, but middle-of-the-road and fun for most players.
But so far all we have are rumors of models, nothing with regards to actual rules.