This is why we shouldn't underestimate Ten Hag. Leverkusen wouldn't expect too much from Ten Hag because they have known his past and hiring him means that they're ready to work with him. On the other hand, Ten Hag will also want to put in the best of his coaching skills into the job, so that Leverkusen wouldn't be disappointed in him.
Yeah when there is no pressure it is easier to prove your worth. The pressure at Manchester United was too much to bear and it affected his performance but let's hope he has moved past all those. Things shouldn't be that hard for him without pressure.
A more tangible change will be seen when the team and coach truly collaborate. When the coach, team, and players are in sync with the coach's strategy, the team will certainly achieve more tangible results. I'll also be watching Leverkusen's performance next season, and I'd be delighted if Leverkusen can make a bigger difference in the Bundesliga next season. Leverkusen needs to be superior to both Bayern Munich and Dortmund next season in the Bundesliga.
Let's hope things go well as you have said, I also don't have doubt about Ten Hag doing well but the question is will he as good as Xabi Alonso? Will he be able to challenge Bayern Munich as Xabi Alonso did during his stay there?
Everyone hopes he can. With his experience he should be able to do so because there won't be any pressure and the league is not as competitive as the premier league.