Hitting most of your shots with an open stance, particularly a full (or near full) open stance, could eventually take its toll on your dominant hip. Apparently, cut short the career of Gustavo Kuerten. Lleyton Hewitt underwent 2 hip surgeries during his career. Both of those guys predominantly used a fully open stance on their forehands. Quite a few other pros and amateur players, who prolifically employed such an open stance, have had right hip issues (if right-handed). My advice is to use a mix of
neutral stances (stepping in) and
semi-
open stances (sometimes stepping in) much as Federer does. He only occasionally employs an extreme closed stance or sometimes a fully open stance on his forehands.
Recovering to the
middle is often
not the optimal position. If your own shot goes to the middle (or middle third) of your opponents side, the the middle is where you should recover to. However, if you hit more to one corner or the other, you should not recover to the middle. You want to recover to a position that bisects the angle of your opponent's possible or likely returns.