@PopeDai: Not if you have hundreds of HttpHandler written already to accept numbers, and already have some other applications/web applications deployed to consuming them already. You can't just change the function signatures.
Btw, if your ModelBinder cannot handle array that has single element (much like a recent case where I need to read a range in Excel that should return 2-dimensional array of objects but Excel just return me string because in that reported case the range only contains single cell), you'd need to write your way to consume it yourself.
As a seperate rant, I'd pretty much like Excel to always return 2-dimensional array if 2 reference is specified, even if they point to the same cell. However, I understand this will break other code so is not likely to happen. Now I wonder where's time machine when you need it.