I think Barcelona might make it to the final or the semis again this season, they have been really good for the past two champions league competition.
Barcelona became a monster that dominated every team they faced, so I don't think their performance in the previous two seasons was any better than what we saw last season. We shouldn't jump into any quick conclusions about the next season just yet, Barcelona might end up in a group stage nobody can tell, but I have a feeling that it will be more interesting than last season Champions League because every team is busy signing players of their choices.
If Barcelona decides not to extend the contract of Lewandowski, I don't think it is a bad idea. The truth is that Lewandowski is getting older, and he is also prone to injuries, which is affecting the team. For the club to sign young players for next season, I think it will be an advantage to the club. The current signings Barcelona is looking into for next season will be good; at least they will strengthen the team's performance in the Champions League next season.
I agree that extending Lewandowski contract is not a bad idea, but the team shouldn't have to depend on him because the striker is getting older and not every player has the same energy to be at the top when they reach 30 or more. Barcelona financial situation is unstable, otherwise, it would be great if the team could sign another striker to strengthen their performance the next season. Lewandowski as their number 9 cannot give them the result they want since he can miss some opportunities due to his age.