My team has developed a game using Flash (with Lua embeded) that targets Windows. And we want to port that game to Android (also iOS in the future).
It's acceptable to rewrite the Flash part of client. And some other team in our company recommended Unity3D to replace the Flash part.
Since we have no experience in Android/iOS development, we would need to learn some new tool/language anyway. So we would like that learning still be useful after the porting and when we starting a new game.
I think it is worth noticing the background of the game : the project is started by a tester and developer, both without knowing much about flex and actionscript. They built the game while learning, so most of the code is hard to maintain. I and other two developers joined the project after a year or so when one has leave (and the other be our manager). The other two developers are just graduates with little experience and little knowledge of flex. I am good at the server part and the c# language.
Based on the fact that the code is hard to maintain (and we do need to change a lot of code to make the game easier to playe in a mobile device), and I am good at c# (and learning). I still tend to do the porting with Unity, which could get better performance and possibly save time.