Quite frankly I don't think Webber has a WDC in him. He's probably as good as Gerhard Berger was or even DC. Webber would make a solid number 2 behind the champion. I think the only drivers out there who are capable of taking home a title are Rakka, Alonso, Button and maybe even Montoya (notwithstanding MS who is the best driver the world has ever seen).
In terms of talent, he's one of the top three drivers currently in Formula One, and possibly I think only one of about 6 drivers out there with the potential to be World Champion (and two have already done so).