The biggest talent i've ever seen in football, Maradona, only really used his right-foot for standing on. But that's genius, you can't really account for it.
I don't think the average player is going to be worse by improving their weaker foot so it does frustrate me when players are totally one-footed. Lamela would not have been a worse player if he could have used his right-foot. In short if you aint a genius, kick the fucking thing with both feet please.
This might not be true, but I did read once that Maradona scored more goals in his career with his head than he did with his right foot.