I think any club that has not performed well in the present season and is not ready to spend good money on signing new players it will be hard on them in the coming season,
The way last season ended, am sure next season will be very competitive, most clubs should be prepared to sign quality player's before the next season is going to start, any club that thinks they performed well in the last season and they don't really need to update their squad before the next season start, they are going to perform poorly in the coming season, next season will be very competitive.
and this is a big sign of potential troubles for Manchester United because if they make the mistake of signing the wrong goalkeeper,
The worst thing that will happen to Manchester united is signing a wrong goal keeper, De Gea made some silly mistakes in the season that ended which really affected Manchester united, if they didn't sign a experienced goal keeper, then they are going to end the season in the position which they don't expect.