Over Polished 2011 Nickel...?

I don't think so, wert. From what I've seen polished dies have more of that empty or open space in the deepest parts of the design on the coin itself, which would be the highest parts of the die, which I think are what get polished and worn, etc. I think what you have is a weak strike, or not enough metal filling the dies at those worn-looking areas (the deepest part of the design on the die), and causing them to come out with little or no detail. Some years seem to have this variety/error more commonly than others -- the 1961 and 1962 nickels, and the early-to-mid 1970's nickels, for example. I haven't noticed it on the 2011's, though. That's a nice example on a nicely conditioned coin!