Ten Hang is not a bad coach as most of us assume due to what happened during his stay at Manchester united. He was just unlucky to sail in a wrong boat with Manchester United but still had two trophies with them before his departure. He was vindicated after their departure and Manchester United did not only finish the season trophyless but almost got relegated with a new coach they considered as saviour.
Ten Hang might make a better coach for Leverkusen and continue from Xabi stop if the club would give him maximum support needed and players he wants to work with.
Let's see if a club like Leverkusen can still be a competitor to Bayern Munich after Leverkusen is in the hands of Erik Ten Hag. No one knows for sure until everything is proven, and I will not praise Erik Ten Hag too much for a career that he has not been able to prove at Leverkusen. The Bundesliga is a different story and, but I am quite happy that he is back as a coach and gets a famous club.