From next season when the league will become most competitive than it has been before now, Leverkusen Dortmund and Bayern Munich will have to probably put up a power tussle which others such as Stuttgart and the rest could join in but they can be sure it's going to be a very different season with the new phase of the bundesliga having all top and average teams having an equal chance to strive again.
The resurgence of Bayer Leverkusen has changed the landscape of competitiveness in Bundesliga. In the past few years, Bayern only had Dortmund and Leipzig as their regular competitor that never succeeded to break Bayern's dominance. The success of Leverkusen to win the league has opened the hope for other teams.
I think next season is hard to predict with the allure of how Bayern is able to buy the best player from their closest rivals, like they bought Dayot Upamecano and Negelsmann from Leipzig. If next summer Bayern buy players from Leverkusen and Dortmund again, Bundesliga will be back to a boring competition again like it used to be. The transfer rumor is starting to mention Stuttgart's best player, Serhou Guirassy, to make a move this summer. Other rumors will appear one by one to target players from these three clubs. It will disappointing if Bayern sign any player from these three clubs, because it will weaken them.