First of all, congratulations on the release of what I consider not just the best pinball game on iOS, but best computer pinball game period. So far, I'd say PS4 version of Pinball Arcade held that top spot for me (because PC version is still not upgraded to have the new visuals) but playing this on iPad - it just takes the cake. It's like having a real, living breathing mini pinball machine behind that tablet glass.
Which brings me to a question: Do you think you'll be able to support the iCade cabinet for Pro Pinball in some of the future updates? One really nice thing about iOS version of Pinball Arcade is that it supports iCade, so with just a little effort, you can create something like this: https://www.youtube.com/watch?v=InBp7GthUQM
which significantly enhances the experience.
I know the iCade is not exactly the go-to controller on iOS anymore, now that iOS7 has external controller API, but I hope supporting it simple enough that you'd consider it.
*edit* I am also editing this post to add a question about adding the accelerometer support for table nudges. If feasible, this could be especially useful with the aforementioned icade pinball mod.