Switching out those blanks for R1 Printscreen, Delete, Home, Insert, R2 Page Up, R3 Page Down, and R4 End would be nifty, and maybe even make the R1 blank for split Backspace into Scroll Lock, that way there's a ~full set of nav keys instead of just blanks.
Just to make it clear, not saying that split backspace should be scroll lock, most likely delete may go there, but using that last blank spot for at least one of the nav keys is a good use.