There are a lot of variables involved here. One critical detail you may not realize is the implication of migrating the product from a desktop to the tablet platform. Because of dramatic differences in how the UI will be need to operate, we have to re-design significant chunks of the UI for the tablet. Each game system has its own UI behaviors scripted separately from other games, so each game system will require significant time to re-work its scripted UI.
Consequently, it's vastly better to do one game system completely before starting on any others. We'll be able to learn from it and refine the process at each evolutionary point in the game's development. This means we'll do a better and faster job on successive games, instead of having to go back and fixup all games every time we discover something that needs to be refined as we integrate new UI functionality.
The bottom line is that, if we were to do just a playable character sheet of each game system first, it will take us significantly longer to get everything done and will assuredly result in a lower quality end product. I can wholly understand the interest in having us do it that way, but it's just not an optimal approach from the standpoint of either efficiency or quality.
Hope this explanation makes sense.
