A sharp leading edge will cause abrupt and irregular stall patterns. The slower a plane flies the rounder the edges should be. In control line aerobatics we learned back in the 50's that pointy leading edges caused the planes to hunt rather than groove. The only time leading edges on anything should be pointed is for supersonic flight. Then they help form the shock wave and control its location. Trailing edges should not come to a point either. That will induce trailing edge vorticies and can induce flutter. The least drag trailing edge at subsonic speeds is actually a thin flat edge with sharp corners at the airfoil intersection. Most folks think that looks like poor workmanship though so they get rounded. Its slower cause it induced vorticies as well but they are not violent and unpredictable like the razor sharp edge (which of course will be lost to hanger and transport rash in short order anyway. Penetration of the air has nothing whatsoever to do with it. The air starts to part to top and bottom of the wing far ahead of the leading edge. Take a look at wind tunnel pics and you will see this pretty clearly illustrated.

keep the oily side evenly distributed,

bob