Manchester United is likely to improve under new management. Ruud van Nistelrooy had an impressive performance against Leicester City, where Manchester United got all three points. This result suggests that the players are not the problem but the former manager was. The players are talented and of high quality. A major overhaul may not be necessary, they should instead buy more players in key positions to strengthen the squad. I am confident that a new manager can make United better than it was under Erik Ten Hag.
Whenever a club sacks a coach, their plan is to find improvements with a new coach but it's plan and hope. Reality with a new coach can be different, and Manchester United understand this difference very well with their own experience. After Sir Alex Ferguson, many coaches hired and fired, and they have yet improved their club competitiveness against other big clubs in Premier League and around Europe.
They want to have better performances and brighter future with Ruben who will have his first season in Premier League. There are many challenges for Ruben, first Manchester United is a big club with lot of expectation and pressure on his shoulder, second adapt to a new league is never easy. He is a very young coach and will be another young coach from Portugal joining Premier League, after two biggest coaches previously Jose Mourinho and André Villas-Boas, one succeeded and another one failed.