I believe that it is not the Xabis managerial talents that would be in question but more like consistency of the roster. After all, we are talking about Bayern that would be all that much better and ready, whereas we are talking about Leverkusen who hasn't won any title in god knows how many years.
Obviously sometimes some teams shock the world, like how Napoli won the Serie A last season easily, and nobody expected them to be that good, Leverkusen could technically do something like that, but will they be still good when it is March? April? I mean they have been good so far and I think it is going to be a little bit of a trouble for them later down the line and that's a lot more important, to keep being consistent during that period.
I won’t agree less with you concerning consistency, a league is not like a cup competition where you knock each other out but it’s a continuous stretch of games to test your skill and consistency level that is why it is the biggest trophy in each country. Last season we saw some European teams being the leaders of their respective league but suddenly fell off and never won the league, example is premier league club Arsenal, Bundesliga clubs Union Berlin who started last season well and later had to be replaced on the top by Dortmund in the last game when they need just one point to win the league but lost it to Bayern Munich.
The above shows that the any team going for titles actually need leaders with characters in the team. For Bayer Leverkusen I think they have those players in Xhaka, Jonas Hoffman and Hradecky. The thing Leverkusen needs most is to keep their fit because it is one of the stumbling blocks for clubs with small depth in squad. If possible Alonso should have new fresh legs in the January transfer market and then try to effectively rotate his players mostly in the cup games to avoid Fatigue setting in