I think there isn't even any need to talk about Dortmund's chances on a Champions League spot. Because it is meaningless. With this inconsistent performance, it is already obvious they aren't going there again. Unless they win the Champions League this season... 

Kovac will be needed more time to make this team decent again. I believe he will make the right moves in the summer transfer window as well. He is a good manager and just needs to put a lot of work into it to clean up the mess happened before him.