I don't think that Hoffenheim can maintain their claim for the title until the end of the season. However Freiburg and Dortmund actually can. We saw how great Freiburg were last season. Maybe they missed their chance of ending in top 4 by a small difference but they were consistent most of the time. This time they have a bigger chance for top 4 as it seems.
We shouldn't overlook Union Berlin also of course. But their end might be similar to Hoffenheim also. I think they will also finish under Freiburg and Dortmund both. Bayern Munich's recovery phase will play a huge role in seeing interesting rankings in the league at the end of the season.
True, Freiburg are more trustworthy for their play and consistency. Hoffenheim still had problems at the end of the competition, either because they were complacent or what. Bayern Munich are in fifth place with a difference of only 5 points, it is not too far away.
It's interesting to see how Leverkusen is working now. They are just one notch above the relegation zone, having just one win and a disappointing 4 defeats. In the last three games they can only collect 2 points.