I also agree with you that Bayern has the higher chance of winning the league than Leverkusen because Bayern players are to smart, sharp and very fast in attacking and you will see how desperate they are to score goals. Leverkusen showed that they prefer to draw the match instead of losing since they saw the pressure of Bayern on them. Bayern has more quality players than Leverkusen which is a good advantage foe them to be better than Leverkusen. I don't see Bayern losing any of their matches soon.
Leverkusen want to use the strategy and technique they used last season and because it did worked for them last season and they won the league title with an unbeaten record along side, they are believing they can achieve same this season even if it's without the unbeaten record, I'm saying this because like you rightly mentioned, in the game against Munich it was obvious they were playing for a draw and it they didn't mind if they don't win, maybe they are looking at drawing with the bigger teams who may pose some threat and win the smaller teams, that way they may be able to accumulate points enough to get to the top but if they continue with the draw mentality, they are most likely not going to win the league title again, maybe they could just finish at the third or second position on the table by the end of the season.
Even if that is likely their strategy in that game and what they want to apply this season, but best approach to that match is as they drew the gam., Bayern Munich isn't a small team, let alone when the game was hosted on Bayern Munich home soil, if Alonso could go back to its drawing board, base on what they last season and even add some spice to their playing tactics, they will definitely bounce back to form and back to topping the Bundesliga table once again.
If Xabi Alonso decides to stick to a particular playing strategy because of it worked for his team last season I don't think there is something bad about it because watching the performance of Bayer Leverkusen last season I enjoyed their performance and the their strategies helped them to win the league without being defeated.
The performance of Bayer Leverkusen against Bayern Munich wasn't bad and despite Bayern Munich dominating the game more but Leverkusen still performed well and took their opportunity to score the first goal. Bayern Munich is currently in a better form than Bayer Leverkusen this season but Xabi Alonso was smart to have advised his team to defend when the opponent equalized the goal which is a good decision, Bayer Leverkusen is doing bad and I believe they will keep getting better as times goes on.