It is so funny to see how things doesn't last forever, look at Leverkusen who won the league unbeaten have gotten their first defeat since last season till the season by Leipzig. This shows that they might not be able to defend the title and a different club might win the league this season. If it happens so, it means that Bundesliga is becoming unpredictable.
Everybody knew that Leverkusen's success last season was something exceptional and nobody expected them to perform equally well this season. If you looked at the outright odds for winning Bundesliga either before the season started or currently, you would see that it was not Bayer, but Bayern who was the favourite all along.
So, if anything, Leverkusen successfully defending the title would be more unpredictable than them losing the title to Bayern.