Unfortunately developing an application for both tablet OS's, at least in the next year, isn't realistic. Working on an app for either OS will take us months, and we'll need to do the same amount of work over again for the second tablet OS we want to support. That means many months of work just on one OS, and that's not counting work we do on other new features and functionality for the PC version.
If I had the chance, I'd have Army Builder working on every device that I could. The sad reality is that our resources are extremely limited, so we need to carefully consider our plans before we take the next steps with a tablet app.