Turnout is definitely higher than we would usually expect for a run of the mill recall -- which is frequently something like half the turnout of a general election. But these recalls were exceptional. Should we have hoped for more? The Gray Davis recall, the only one that really imprinted itself on the people's minds, saw much higher voter participation than in the 2002 general election that elected Davis.
The Wisconsin results seem to be a little below par with the off-year general election in 2010. I say seems because we can't make a direct comparison. All of these seats are only up for vote in a presidential election year (2008 , 2004), which sees a much higher vote total than an off-year election. Looking at the comparisons from the piece by Craig Gilbert, all but one of the five races appear to have less votes than in 2010. (Can't say about Darling's seat just yet).
Since the closest race was actually won by a Democrat, it's hard to say how much of a difference a better turnout would have made. It could possibly have helped the Democrats carry the Olson seat, but they would have needed at least 2,000 more votes in a race that saw a shade under 51,000 votes cast.