>> It's generally a mistake to make the initial development more pleasant at the expense of long term maintainability;
Me and my friend are working on this game [1]. I have prototyped all the game logic in Common Lisp (using both LW Mobile trial edition and MOCL). We could really quickly iterate the game play and reach a design where the experience will be fun.
But to get it working with 60 FPS, we are writing the game now in Swift. A lot of our game asset pipeline is also in CL and Python. So as per my limited experience, I would prototype the game idea in CL; also use more powerful tools for offline utilities etc but ship the game in whatever is the best toolkit for that platform. In our case, Swift, SceneKit and SpriteKit.