Personally, I think the 100 WR macro is a limited in disguise
I went on a trip a few months ago and my two most used lenses were the 35/2.4 DAL and the 100 WR Macro. Covered a lot!
I owned the 50-135 but prefer the 100. When using the 50-135 I was usually at the long end anyway, so I get (much) closer focusing, sharper optics (though the 50-135 is no slouch) and a lighter build in the 100 WR.
Since the 50-135 is internal focusing, the extra reach on the long end might not amount to so much if your subject is close.