this seems like it would be very impractical. There are way too many aspects and exceptions and inclusions and so on that would have to be accounted for, in order to make this feasible. It also seems like it'd take some of the fun out of battles - joining and seeing, say, a 70% chance of your losing doesn't seem super fun for you as a player. There would also be a lot of questions to answer to do it right - how would you calculate and weigh the effectiveness of a move in the overall win chance, for example? Obviously, subject to change based on your skill, but that still seems unfun. In general, there seems like there would be a lot of moving parts and a lot of work for little gain, since luck is difficult to account for, and a large part of the game, so I personally don't see much of a benefit, but that's just me.