I don't think Dortmund will be a fierce competitor in the Bundesliga title race this season, they have undergone a lot of changes and on the other hand Bundesliga teams like Leverkusen, Leipzig and also Bayern have improved much stronger, it is the opposite of Dortmund so I doubt a little that Dortmund will compete fiercely in the title race especially this season they have a new coach of course every new coach needs to adapt in building a team as well as for Dortmund's new coach this season.
This season Borussia Dortmund has not performed badly. They have won one game and drew one in two games. They are even better than Bayer Leverkusen which has just three points in two games. They have a new coach, Nuri Sahin, who is not new to the Bundesliga, having worked as an assistant coach in Dortmund before he was appointed head coach. Four points from two games is not that bad, and hopefully, they will improve after the international break.
Maybe we might have some new team finishing in the top five places. Heidenheim is the current leader of the league and they are one of the three clubs (Bayern Munich and Leipzig) with six points. They might be a wonder in the German League if they remain consistent. In most cases, such early league leaders lose steam and end up in lower positions.