I said it before the season Mirallas doesn't suit the left, he will contribute for any team when on form but it doesn't hide the fact he doesn't suit playing on the left positionally, just as Kone is starting to show the exact same problem.
It worked perfectly with Pienaar because he would drift a little but always be available on the left rarely would you see Pienaar pop up in a RW position like Mirallas and Kone will during a game in frustration of not seeing the ball and thats why we have become unbalanced again like we were in the years of Baines and Pienaar and nothing down the right.
Yarmelenko isn't the answer either when we were linked with him, great for the right side but another player who likes to cut in from the right won't suddenly want to hug the line on the left or cut in on his far weaker foot.
If we keep Geri which i don't see any real possibility of losing him (still incredibly raw at times) then the left has to be a Pienaar, converted #10 type player who drifts around a bit but provides a good balance, Dries Mertens would be my choice for that type of role