Isn't this just going to remove the challenge of the game? if you can just use auto combat to decide how well you would do and if you don't like the result simply attempt to fight it manually it.
Maybe im just old school when it comes to gaming , to me its not about home many hours it took me to finish the game or which one of my mates did it first, its more about the struggle to get there. I Never ever re-load in x-com , if i loose my Rambo , than i start training another one , Yes it hurts for a while, i may even cry but at least then im experiencing the struggle that is X_COM. Also the only time i save in combat is if i have to stop playing, this is how ( i believe ) the game is meant to be , otherwise you loose the fear and the heartache and the struggle to try to save humanity.