Forgive me if this feature already exists... I couldn't find any reference to it in the Options.
My feature request is to be able to define in Options what double clicking on a track does.
Currently it plays the track in the default system player, which can be handy, but I would have more use for it to open the Extended Tags form.
I'm sure others would have additional desires, but for me this would be the one I would pick if there could be only one alternative.
So in summary: I request the ability to choose between "Play Track" and "Open Extended Tags"