Williams is quite similar to Vermaelen in style in that he's a last ditch type defender who's more reactive than proactive which supplements Chico Flores in style. That's why I feel he'd supplement Koscielny as well. He also shares some leadership qualities with the Belgian although there have come question marks over the latter's after him getting the armband. However, he also has the exact same height as Vermaelen so isn't very tall for a central defender (6 ft) - especially when you put him alongside Koscielny, we're going to lack height in the side against the Stokes and Sunderlands of this world.
At the start of the season I thought Williams looked poor. His fumbling with ball resulted in a couple of embarrasing goals for the opposition and in general his passing leaves a lot to be desired so Vermaelen has a definitive edge on this front, I feel. However, as the season progressed you have to say that Williams was one of the best CBs in the league during the mid part of the season.
All in all I think he'd be a like for like replacement for Vermaelen but he lacks experience at the top level, he's not getting any younger so there's not a lot of room for improvement and his passing is quite poor but you can say the same about Mertesacker's so it would be a gamble. But if he would be content with being the 3rd choice defender, I think it's worth a gamble.
As for the reported fee. £12m is having a laugh. Wenger's highest ever transfer fee was £15m ffs!
