From a designer standpoint, I prefer to stay as in character as possible and give simple explanations of how things work. Not everyone is into seeing numbers. It can take the mystery and adventure out of things if you aren't careful. There's a lot of excitement in not knowing what your next spell will do.

The people that are into mechanics will test and figure out every combat formula you've done anyway. In my experience they usually compile this information and share it with other like-minded players as well.

So yeah, really depends on which crowd you are catering to.