I agree that Leverkusen was always strong and they were even racing at the top of the table with Bayern Munich and Dortmund but they are much stronger this season with their coach Xabi Alonso. They had a good performance in the last season but Leverkusen didn't have many good players and the team tried to help Xabi by hiring the players he needed, that is why they are in the top side of the Bundesliga because Xabi Alonso was a great advantage for them.
Xabi Alonso success in managing Laverkusen this season has been phenomenal, going seven games unbeaten and topping the Bundesliga standings. I see Bayern Munchen dominance starting to be threatened even though they have better squad depth than Laverkusen, but in terms of strength I think they are quite balanced. The draw in their second meeting in the fourth week is proof of Laverkusen strength this season, just waiting to see how Laverkusen strength will be when facing Dortmund.
The Bundesliga standings have become more competitive with Laverkusen consistency in winning points, if this continues their chances of winning a trophy at the end of the season are wide open. Thus, Munchen decade-long dominance was broken by their own former midfielder Xabi Alonso. Dortmund almost did it last season, finishing on the same points but falling behind in the goal statistics.
So far in the Bundesliga, we know Bayern Munich has a much better squad than other teams like Dortmund or Leverkusen, and even Stuttgart, but still Bayern Munich couldn't get good results like these teams got so far in Bundesliga games.
Stuttgart's performance was amazing so far thanks to their palyer Serhou Guirassy and Leverkusen got a coach like Xabi Alonso who is a great advantage for this team.
Xabi Alonso has made great strides in his coaching career. He really made a great start at Bayer Leverkusen. If we look at the team rosters in the Bundesliga, of course there is no team as qualified as Bayern Munich, but while Leverkusen plays with all its spirit and gets good results, Stuttgart is at the top of the league thanks to its magnificent striker.