it can only be good - at least for crop.
ZoomPlayer IS excellent and far better to use in this respect than MC.
I have LOTS of videos that are 4:3, but have borders (i.e. non-anamorphic widescreen). On a widescreen telly in MC that ends up being really annoying, because you then end up with borders at the top and the bottom and both sides! There's then no option in MC that can solve that, but in ZoomPlayer, you just zoom until the sides of the video reach the sides of the screen.
I've wanted this in MC for ages.
The other thing that would be great would be an EASY way to switch between them - this is actually the one thing that stops me using JRiver Media Center for watching video/DVDs and leaves me using Microsoft's Media Center, because that has all the options easily available on a couple of button presses (this is the main thing I do in JRiver MC regularly that I can't do without using a menu, which isn't easy from a 'standard' remote control).