Alexis Mac Allister is a midfielder who plays well, his performances were impressive when he wore a Brighton shirt last season, and indeed Liverpool's current need is for a midfielder who can give color to Liverpool's game. But of course that still has to be proven on the field, because even last season Liverpool failed to buy players.
Alexis Mac Allister is a player who is predicted to make changes and he has to answer that with a good game. Because last season Nunez was also predicted to be a player who could make a contribution to Liverpool, but as we know he failed to give his best for Liverpool and was considered a failed purchase.
Too much expectations from a newly signed player is not always the best. Some players take much time before they’ll bond with the new team and make changes or add their own expertise to the squad. Haven said that, if the other team players are not helping with matters, not contributing effectively as the new player, all his effort will become futile and it’ll look as though he couldn’t fulfill his duties well after spending so much money to purchase him. The case of Nunez should not be repeated for Mac Allister, hopefully he’ll blend early to the team and make the team progress by next season.
Liverpool were too unstable throughout the season, why this happened is not clear, but sometimes teams have recessions. At the end of the season, it looks like Klopp has found a way to approach the players and the team has found its game, because at the end of the season they were again like the old Liverpool. How they start this season, we'll see, Klopp requires players to give everything in every match, it's hard to keep up with the whole season, so the team needs fresh players.
As you said, teams always have unstable period where even the coach doesn’t know the next step to take when the players have being playing woefully. How smart a coach is will determine how long those players will be underperforming. Klopp was able to realize that early and it improved their game before the end of the season, which eventually gave them a ticket to the Europa League. They just need new addition of players to the team, I’m sure Liverpool will do better by next season.