Van Gaal is hoping to mount a serious challenge for domestic and European silverware in the coming year after qualifying for the Champions League in his first term in charge.
Despite spending over £225million since taking over, Van Gaal still thinks his squad lacks speed and creativity in attack.
The Dutchman is therefore on the lookout for a talismanic forward who will help put United on a par with their domestic and European rivals.
“We need still more speed in front and also more creativity,” the 63-year-old said on United’s pre-season tour of the United States.
“That is why I hope (Angel) Di Maria shall stay. But we don’t know that (he will).”
When asked what kind of player he needs to make United true competitors in the coming year, Van Gaal added: “I can give examples of champions, Bayern Munich have (Franck) Ribery and (Arjen) Robben, Chelsea have (Eden) Hazard and Willian, Real Madrid – Ronaldo and (Gareth) Bale, Barcelona have Neymar and (Lionel) Messi.
“Manchester United fans want us to compete with these teams so we have to look for those kind of players.
“We can use much more creativity. We look for more creativity. You need creative players. For example, Chelsea have Hazard, Willian and Oscar. There is a lot of creativity there. And you need that because you have to disorganise (teams that park) the bus. Next year there might be more teams who are parking the bus.
“Now we have Wayne, Mata, Depay, Young, Januzaj, Wilson, Herrera. So you can expect from Young, not that he is a Hazard. You have to compare. Young has had a fantastic season but he is not a Neymar and we have to compete with that kind of class.
“Young and Mata had fantastic seasons (last year), with assists and goals, but to win the Champions League you need speed also.
“That is why I think, maybe, we still have to buy a player with speed and creativity.”
Ronaldo would certainly fit the bill and has been, rather spuriously, been linked with a return to Old Trafford recently, but Van Gaal admits it is unlikely United would be able to re-sign him from Real Madrid.
“He is a fantastic, fantastic player but he knows that. I like him,” Van Gaal said of Ronaldo.
“But it’s not possible (to sign him). Why not? Because you have the club (Real Madrid), Ronaldo and then you have Manchester United and how much Manchester United want to spend.
“But when it is possible to buy for a reasonable price players from that level we shall do that.”
Van Gaal’s preparations for the new season have gone well so far. United beat Club America and San Jose Earthquakes before defeating European champions Barcelona in Santa Clara on Saturday.
United round off their tour in the early hours of Thursday morning when they take on Paris Saint-Germain, who want to sign Di Maria, in Chicago.