Now regardless of what happened to Dortmund last season, they should try to play better this time, but if you look at the beginning of the season, it is inversely proportional to their performance in the previous season.
Indeed, for the beginning of last season they were also almost the same because in the first 10 matches they could not play well but this means that they have not changed and their performance remains the same as before which makes hope in the Bundesliga competition this time most likely will not be seen again.
As for Leipzig, no matter how bad or good they are at the beginning of the season in the end I still think the top 4 is their place only for the title competition even if they play well they still won't be able to do that now.
In the Bundesliga, where Bayern Munich frequently overshadows the hopes of smaller clubs, it is a tricky scenario. Last season Dortmund had a chance to beat Bayern, but they blew it highlighting the enormous mental and physical gap between them and Bayern. Leipzig consistently earns a berth in the top 4 while occasionally being unreliable. Although they may not be in the running for the championship right away their season long performance has been promising they are now third with just one loss. This implies that they might push Bayern for the trophy in the future. Dortmund missed their moment to take advantage of it, but it is feasible that they'll improve in the future and try to unseat the current champions.