What Evans' problem before 2009 seemed to be was that he didn't have a big win. His ability deserved a big win, but something always stopped him. Often it was him himself; an unwillingness to attack when it was necessary or a tendency to attack when it wasn't advisable hurt him. Another problem was that he either seemed more comfortable once there was a reason for not winning (eg sitting idly by and not attacking once after the puncture in the '09 Vuelta), or if things weren't transpiring as he hoped he would get the sulks (Ventoux stage of the Dauphiné). All the while, people of comparable and even lesser talent were compiling better palmarès than he could.
What the 2009 Worlds did, was get the monkey off his back. He COULD get the big win. He had timed an attack right, and he'd got a massive win and deserved it too. Now it seems that the sulking is done. He knows if he goes out and gets it he has a good chance of doing so, he actually looks like he believes he can win.
When something bad happens, it looks like he goes out to correct things now.
It's just a pity for him that this transformation has probably happened too late for him to actually win the Tour.