On the one hand, Marco Reus was one of the players who was quite disappointed at the end of the Dortmund vs Mainz match because he really dreamed of a Bundesliga trophy and he failed to get it.
He was came to Dortmund on 2013 which mean one year after Dortmund became an Bundesliga champions and when he comes to this team Reus was hope he can gets the trophy with Dortmund because at that time Dortmund were very solid under Jurgen Klopp but in fact Dortmund indeed has been several times to compete for race title with Bayern but they were never can make it again
And this season when Dortmund were very close to the title but in the last match Dortmund were failed to beat Mainz which mean Bayern automatically is the champion of this season so it's normal if he feeling dissapointed because during his career with Dortmund all he want is to get this title and for next season it wouldn't be easy because i am sure Tuchel will be evaluate Bayern performance and they will be more solid than now
Disappointment comes to everyone when watching Borussia Dortmund fail to become champions, who are thwarted in one game and only 1 more goal is what they really need. Marco Reus will clearly feel the disappointment, he has been at Borussia Dortmund for a long time and every season works hard to bring Borussia Dortmund to the championship. Even when I go to the media, he is one of the players that gets talked about a lot. Netizens say they want to see Marco Reus holding a trophy more, than Borussia Dortmund itself, I don't know if this is a joke or a criticism, but it proves that football fans want to see a new champion.