Hm it is true that Freiburg did well in this season. I didn't expect from them that they would play such good gameplay in this season. But yeah, Leipzig is still good to play on champions league. Dortmund is not playing good what I expected from them.
The match is totally open. Team-wise, Leipzig is better. But Freiburg is playing a fantastic season and has a talented team and they have the momentum. Leipzig, on the other hand, was unfortunate to be knocked out of the EL and didn't perform well in the league after that. I would even slightly favor Freiburg.