This is really cool! Sadly, I don't know if it is something that hasn't already been done. The JVN calculator (
http://www.chiefdelphi.com/media/papers/3188 ) is basically this spreadsheet with many more features. I'd encourage you check that out if you haven't done so already.
That being said, it's GREAT that you are trying things like this and I would love to see you try out new things. The JVN calculator covers a LOT of things but there are still many features that it lacks. Perhaps you could work on something like calculating the Spool-up time of a wheel or a calculator to tell how long it will take your robot to drive to a certain distance. Figuring out aspects of individual mechanisms and designing calculators around them (I.E. a calculator for the release angle of different types of shooters or the efficiency of an intake) would be something that takes the type of calculations done by the JVN calculation and applies them to specific aspects of FRC.