[Longhanks]

There is never a good way to write cross-platform apps. Cross-platform programs are always inferior to solutions specifically designed for a particular use case (e.g. touch input + mobile device, pen input + tablet device).

[tomjen3]

I agree there needs to be a platform specific input output layer, but assuming you are writing the same app on different devices there is always going to be a large core (essentially all the business logic, all models, all validation, all sync code) that is, or should be, the same on all platforms. It is that code I wanted to refer to.