Yes indeed, at least if Dortmund managed to get the Champion League trophy, it would certainly be a very impressive farewell that Marco Reus would experience. But what happened might not be so good because after all, throughout the match the score was still 0-0 but in fact, when Marco Reus was inserted as a substitute and not long from that Real Madrid actually managed to score a goal. Indeed, I don't blame Marco Reus either but at least, because before this moment would be a good farewell moment, but maybe because the process goals happening like that might be something annoying. But yes, it doesn't really matter because after all, Marco Reus himself still managed to make Dortmund finish in the Champion League zone in the Bundesliga standings and of course, Marco Reus remains a Dortmund legend because Marco Reus loyalty is so great to Dortmund.
Whatever teams play in the final, there are always those on both sides (Reus and Kroos for example) who are worthy and for whom this is perhaps the only chance in their career, but there is always only one winner, such is life.
As for the ticket to the Champions League that Dortmund received as the fifth team in the Bundesliga, this is literally the merit of Dortmund - if they had not scored points in the games with Atlético Madrid and PSG (and before that at the group stage in the group of death) for UEFA rating, then England would be in second place with 5 teams in Champions League.
Before the final of this season's UEFA Champions League competition, Borussia Dortmund's forward player Marco Reus have already announced that he's going to leave the club at the at the end of the season while Real Madrid's legend Toni Kroos who happens to be Marco Reus compatriot have also announced that he's going to retire from football this summer making the final the last game for both players in their respective clubs. The both clubs needed to win the final so they can give their legends a befitting send off.
Real Madrid finished the game victorious and Toni Kroos got the best send off he would ever have wished for because he didn't just win the UEFA Champions League in his final game at the club but also became one of the four players in the history of the UEFA Champions League to win the competition in six different occasions.