Free agent means there's very little risk though. What's the worst that could happen? We'd waste some wages? If Ben Arfa works out we have a top class winger for free next season. If not then we'll just play Ramsey on the wing which I'm pretty sure is Wenger's plan anyway.
Basically, if he could give us one or two good seasons before he switches off again it would be worth it. There are no better wide players in this league when he's on song.