I like reading this because this is more or less the direction I envisioned for the project: I had in mind a third ability for characters that you need to hold a button for a while to execute (and so it requires good timing), new characters with different abilities, and enemies with different patterns and abilities that will require you to change you team. And as I explained in another comment, I was planning on "absolute" key mapping, but I don't know why I changed it at the last minute (I thought it would make more sense to people playing on a keyboard)... The tab key is nice though, I might steal this idea :D
Thanks again for your feedback, it fills me with determination to build on this idea!