I don't think a complicated system with the gamer fighting instead of the character would work. I'm afraid it will be as in a Fifa game. You suck the first few days, get the hang of it after a week and after a month the highest difficulty setting won't even be a challenge.
You can dream about a perfect fighting system, but never will something like that be complicated enough after a while. And personally I get sick after repeating something like that over and over again (as playing matches in fifa when you are doing something like a season or career or whatever, or fighting every battle in (Rome) Total war). 'Get on with it, get back to the game'.

With magic it is easier, than you really can make a strategy (if there enough different spells available). To resemble something like that in the fighting system, you would need different moves that have different effects. But, to be honest, I can't picture something like that in my mind very well.