I've had this idea for a while, and was going to try it on an old bat.
What about on the edges small grooves cut in at approximately 45 degrees (open to variation) from face of bat to back. (Higher at the face end) spaced roughly an inch apart
The effect of this could be that balls which clip edges are directed towards the ground (sorry bowlers and slips).
Not sure on the legality of this
A bit innovative like when woodworm put scoops out.
Anyone with better IT skills than me (MS Paint amateur here) might be able to notch up a design.