Van Gaal was installed as the Scotsman's replacement in May after the ex-Everton boss failed to keep the club in the top four after he was hand-picked by his predecessor Sir Alex Ferguson.
Despite Van Gaal guiding the Netherlands to the World Cup semi-finals in Brazil this summer, Neville believes that a major overhaul of the squad would be needed for United to return to dominating ways.
"I don't think he'll be a revolution unless they sign seven, eight or nine players," Neville told Sky Sports News.
"I think that at the moment it will be a case of getting the maximum out of the players that are there, and organising himself quickly into understanding which players he wants to move forward with him. But his experience is enough, and I do think he'll do well."