He would be expensive, and we know Wenger no like spending large money.
Hazard is exactly the kind of player Wenger will spend money on, though. He's perfectly willing to spend money on good, emergency signings - Nasri, Arshavin being the best two examples - but won't spend money needlessly on someone like Cahill when he can sign someone better, or just as good for less.
Genuinely think the only thing stopping this going through is whether Hazard wants to move to Spain. If Lille say they want more than £20m then it's perhaps unlikely Arsenal will go for him at this stage but I don't think they're in a position to tbh. Still cautious about the deal, though. I don't want to get my hopes up..