Well, I don't actually think Vincent company is a bad coach regardless of the fact that he took Burnley to relegation last season in the English premier league, but one thing I have observed in this Bayern Munich team is that they are still trying to get used to his playing system and I believe that if the players can acclimatize to his system very fast, they will definitely be a major force to reckon with in the German bundesliga once again.
Then talking about the defense of Bayern Munich and how weak they are at the back, sincerely speaking, that is one major thing Vincent company really needs to fix because they can't out score all the teams in the German bundesliga, their are teams that are extremely difficult to breach their defensive set up, and against such a team, if they can't hold their defense properly, once they score you first, everything is over, because at that point, they will likely get more goals than Bayern Munich equalizing, so it's very much important that they fix and get their defense kicking and running, if not, they might suffer the same faith as last season.
If we think about Vincent Kompany when with Burnley and Bayern Munich, actually it's something unfair. From the competition for each league is very different and in a condition of the squad is also different. Although Bayern Munich has a much more professional squad, but there is something we don't know that makes Bayern Munich a little difficult to get back to get the bundesliga title.
As you said in the weak defense that is the main problem at the moment. Vincent Kompany has tried to improve these weaknesses and if they still have the same performance, Vincent Kompany must be demanded to find the problem and immediately fix it. Pressure like this that usually makes the coach difficult to find the right strategy.