cinqcepages,
I own an M1ViNL and can concur that while I love it for MM cartridges, it lacks a bit of gain for low output MC cartridges. I think your experience with your CD front end proves the rest of your system is up to the task.
First, if you're sticking with the Legacy I would make sure it's properly aligned and that the stylus isn't worn. After checking that, I would look to a phono preamp with more gain so as to be a better match. For my MC carts (currently a Zyx Airy 3SB @ .24mv) I'm using an E.A.T E-Glo Petit which sounds great and has plenty of gain, but there are lots of options, including keeping your M1ViNL and getting a step-up as mulveling suggests.
Gregdude also has a great call out on making sure your TT has proper isolation. I'm fortunate to be on concrete in my basement, but I've used both granite and butcher block in situations where my floor wasn't as solid.
David