Currently Scott Walker holds a very narrow spread of +0.4 according to the Real Clear Politics Average. However, it appears that Real Clear Politics tends to overestimate the GOP vote in WI gubenatorial races.
RCP Average Outcome
Recall R+ 6.7 R + 6.8
2010 R + 8.7 R + 5.7
2006 D + 6.0 D + 7.4
If you average these three differences then it comes out to Democrats outperforming the RCP average by 1.43 points.
Do you think the RCP average is currently overestimating Walker's support?
Quite possibly, but this is the sort of thing that's true until one day it suddenly isn't (like Virginia always electing a Governor who isn't from the President's party).