I can see why Wenger is interested. I have always thought Flappy would be off this summer, so naturally we'd then need a new goalkeeper. Cesar, for me, is a better goalkeeper than Flappy, and roughly at the level of Sneezey - we would then be marginally stronger over all in that area.
Then again, I never really felt we needed a better goalkeeper to begin with, so I am not fussed either way. I reckon someone of Cesar's age and background would do well in our squad though, and he is someone Sneezey could learn from at least.