Make cell style a valid criteria for logical functions!
Let's say I want to find all the "good" styled cells in a column and add up their values. Normally, I could use a sumif function, but as far as I know, excel does not support cell style as a logical criterion. Allowing this would let me use sumif to pick all the "good" cells in a column and add them. Tying this in with conditional formatting, using rules to set good or bad cells, would make functions and formatting tie in quite nicely.