Although Bayer Leverkusen has been leading this season, I can't say or believe that they will win the league. Everyone wants to see a team surpass Bayern Munich's records, which have stood for more than ten years, but it's very difficult to do. As you mentioned, Dortmund tried to do this in their final game of the previous season, but Munich ultimately came up and won the league. Even though Stuttgart is already in the top 2, their performances this season have really taken me by surprise, it will be difficult to predict for the time being whether Leverkusen will stay at the top to win the league. Leverkusen is currently leading Bayern Munich by just two points, and while I do not believe that Leverkusen will be able to win every game they play until the end of the season, I am still unsure that Bayern Munich will win the league at any point this season. They are not as weak as people may perceive them to be based on their performances.
I'll be very suprised to see Leverkusen win the league, it would make them more stronger cause the board would invest more into the team, well it would be nice to see another team dominate the League and make it more competitive cause there's less competition since one team have been dominating for over 10years, Dortmund were almost close last season but couldn't achieve, but it Leverkusen does it this season it would boost the rank of the club and also boost the profile of their manager Xabi Alonso and the players as well.
However i love how far they've gone, with the rate of how successful they're currently many teams in the league are now scared of facing Leverkusen and i believe their success rate would build their confidence level more and if they don't win the league they would definitely be in the top 4.