First note, you should change your subject from MBps to Mbps because there is a significant difference between the big B and little b.
Lastly, I don't see how this will increase quality all that much. Canon chose it's current setting for a reason and I doubt it was because the camera couldn't handle a lower compression rate. I think the real increase in quality will come when we see 4k x 2K HD video from the 5DII.