The Mac plug-in is the same code as the current Windows plug-in, there are no differences in terms of features. We're working on new features for the plug-in but I can't give you a release date for the next update yet. We'll release the next build simultaneously for both platforms.
I'm guessing there's something devilishly wicked involved in trying to make the Mac M~R plug-ins for LW...or perhaps for making any plug-ins for Mac LW? (maybe there's a good reason only about 10% of plug-ins are available for Mac as well as PC...crazy SDK difficulty with LW Mac?)
I wouldn't say that the ratio of Mac/PC plugins is that bad. The reason some LW plugins are PC only is often that the author is just one person without sufficient resources to develop for both platforms.