It's hard to really say much or little. At the beginning of the season everyone wrote Leverkusen off, but now they are four points behind Bayern. Only half of the season has passed and if Liverkusen remain stable, then we can start to think that it is dangerous for Bayern, but now I agree with you that they are very far from the first place, Bayer play a lot of draws.
The pressure from Leverkusen makes the competition more challenging, Xabi Alonso just needs to maintain his team's performance so as not to slip under any circumstances to keep the competition alive. Anything can happen in the second half of the season, including Bayern Munich dropping points like they did against Mainz. The four-point gap is not too far, there is still a possibility of a change in position if Bayern Munich is unable to maintain the consistency they have shown so far.
Dortmund are looking to get back into the top four, they could spring a surprise in the second half of the season having been a regular team to qualify for the Champions League. They are also a threat to other big teams because they always appear different when competing in Big Match games.
In first half of season we have good challenging games with Bayer Leverkusen after having few poor results now back into business which is good sign for them with this improvement we will have another interesting half of soccer in coming days with this we will be able to have better view about Vincent Kompany abilities because he is currently on better spot as coach of Bayern Munich and his start is encouraging but while in coming rounds we will have good pressure where we need better leadership so can he manage things for having success.
Xabi Alonso is surely one of the most talented coaches of this era who is learning quickly from his mistakes and doing good work for improvement January window is going to be interested because they can bring few players for strengthening of their squad which will surely good for them and heir chances of winning another title.