Even if neji blocked the points it wouldn't stop the sand cause I basically has a mind of its own. Also neji can only block the points if he can get past the sand. Which I doubt.
But Lee never used gates on Neji; which is something makes Lee superior to him combatwise.
Gaara would take this one; Neji could deflect one or two attacks of sand; and that would be it for him. He does not have much of a chance to use speed against Gaara; that was not his own speciality. Gaara would crush him.