I mean he is going to be expected to be successful in not only Bundesliga but also there this time. If I elaborate "success in the CL", I assume the expectation would be to qualify from league phase at least.
Can they do this though? If we see another dedicated effort this year too then why not? With that kind of a performance they can even beat some of the biggest title contenders.
I will not say Leverkusen is bad or Alonso will not be ready to face the challenge in the UCL but in terms of competition in the UCL it is very tough because there are so many top clubs with more experience to be able to win the title and on the other hand Leverkusen so far has just achieved the achievement of winning the Bundesliga title and it is too early to be able to compete in the UCL until the final or semi-final round.
While defending the Bundesliga title is not easy because now Bayern Munich seems to be recovering soon and fighting back to seize its dominance and Dortmund will also complicate the competition for the title.