Real Madrid can be considered superior, based on the last 5 head to head matches between Real Madrid vs Dortmund in the Champions League. However, we must know that Dortmund's last 5 matches recently, Dortmund is very favored with 2 wins in the Champions League and 2 wins in the Bundesliga, and only experienced one defeat in the Bundesliga match.
I think the Champions League Final this time will be very fierce for El-Real, considering that Dortmund's defense is difficult to penetrate and has conceded fewer goals than Real Madrid, and it is very likely that there will be extra rounds, or even a penalty shootout to win.
The possibility of the match extending to the extra time is still little because both teams from their past head to head meeting have clearly shown who is at a bigger advantage than the other. They have both come a long way to the final, so no one will be expecting less from one another, it’s just the facts and reality at hand that making one superior over the other. Real Madrid have the highest chances of winning this league but that does not guarantee them a easy path to it because Dortmund will try their best to stop them even though their best can be matched with Real Madrid’s prowess. A lot of speculations have been going on the team that will win but realistically, until the match is played before the real winner will be ascertained even after all this statistics from both teams that clearly shows who will win the match.