No, Leverkusen don't look weak this season, it's just that Munich aren't as weak as last season. Munich have some quality players and that's why it's hard for Leverkusen to compete like last season.
We can't deny that Leverkusen is weaker in this season. Meanwhile Bayern Munich becomes stronger under Kompany's management. Regarding the squad quality, I don't see significant change. It is only about the decline of Leverkusen performance. Other teams in Bundesliga may be improved their performance, they also may know better Xabi's tactic. So they can deal with Leverkusen game this season.
Leverkusen is like a one-season wonder team. Their performance last season was truly invisible. If only they had won the UEL then they would have become the first team in history to achieve an invisible treble where they became champions without being defeated in all competitions. After that magical season ended people have started to analyze Alonso's tactics well and that makes Leverkusen this season look weaker than the previous season. Plus some of their star players have moved to other clubs. Basically Leverkusen is not a team with qualified individual quality but Alonso managed to make them a solid team. Leverkusen's weakness is that they will be weak when under pressure from one man marking like Atalanta did last season.