The grill on the new 2 series looks great.
If BMW really want to differentiate the M's to the non-M's, they do not need to do too much.
I would have added something like a recessed grill frame as seen on the CSL hommage for instance, to give it a more 3D appearance.
This, along with a more aggressive and tidy bumper design would be more than enough to differentiate it from the non-M's and would transform the design.