It is very likely that both Bayern Munich and Bayer Leverkusen are going to win their away matches and for Bayern Munich this should be easier than for Leverkusen. I think Wolfsburg isn't a very good team, but also not a bad team, which means that they can resist some pressure for some time. It is still weird that Cologne is sticking to their coach and haven't done anything about it yet. But there has been some negative trend since two seasons ago when they finished 7th. In my opinion at the end of the season they could be in the relegation zone this season.
I only believe in Bayern Munich, for Bayer Leverkusen, even though the bookies favor them, there's a tendency that they will also get a draw in this match. Bayer Leverkusen's winning streak isn't an ordinary thing, it is not natural that they will get positive results continuously, that's the reason I'm not sure that Bayer Leverkusen can win easily against Werder Bremen.
Regarding Koln, they're currently in the relegation zone with Union Berlin, it's not impossible that they will be relegated at the end of the season considering their current performance.
You are surely right, betting on Bayern Munich is definitely a safe bet because Bayern Munich is a team with much more potential and they can have a much higher chance of winning the Bundesliga title than the other teams even against Dortmund and Leverkusen, they can definitely have a good chance.
But the fact about Leverkusen in this season is about their coach Xabi Alonso, his performance was definitely awesome and he is the only reason for some people to bet on Leverkusen for the end of this season.
I think the odds also have an impact on betting on Leverkusen. As a surprise, I think there are people trying to make money by betting on Leverkusen. If Bayern does not win the championship this year, everyone will be very surprised because they have a championship hegemony that has existed for years. They have the power to continue this this year too.