1st of all, if a batter is looking that far right of the pitcher, he isn't seeing the pitch or is looking at a pitch that is going to sail waaaaayy outside the strike zone.
In my opinion, the extra wall is totally un-necessary and the LT center isnt in the batter's field of vision. The center field wall is plenty big enough to provide a background for the space in which a pitch will travel. The only instance in which I could imagine that the building would be in someone's field of vision would be on a relay from RC.
If someone is really, that concerned, they should build the extra-wall all the way around. Because looking out into left-center you got a light blue sky that can be difficult to pick the ball up in. Same for left, right, and etc.