We are not in a position to wait on players, to be honest. People are talking about Sancho, but we have to at least get Champions League this season (I don't think we will based on our transfers) and even then he will have a host of clubs after him, if he repeats last season's form. It is far from guaranteed, so we might end up with no right winger again.
We needed a right winger this season because our attack is far from good enough. It is lop-sided: we only attack from the left or the middle, which makes us easy to defend against. I don't see how we are going to play attractive/effective football when we are effectively playing a 4-3-3 with nobody on the right. Lingard and Mata constantly go into the middle, so most of the time our formation ends up like this:
Martial --------- Rashford ----------- Huge Gap
Lingard/Mata
Pogba Mctominay
Matic
We are going to regret not buying someone for the right wing this year. It also affects our counter attacks, since they only usually have to deal with Martial and Rashford so it is constantly two defenders against one attacker. With a right winger there would be three attackers, so that situation should not happen.
It was a critical position to sign a player. Annoying that a team who scored the third highest amount of goals last season (Arsenal) ended up signing another goal scorer for the right wing (Pepe), but we did nothing.