Just be a little patient man...
We are still in the beginning of the season you can't say that Bayern is going to win everything again.
Many team such as Real Madrid are still dangerous and competitive and can win Bayern in knockout games.
On top of that, many things can change during the winter transfer window - Bayern might be weakened who knows...
Koeman was the right coach to get the Dutch team back on track. After he become the coach the reached the finale of the Nation Legaue after a few years with qualifing for the Worl Cup/European Cup.
If he does the same for Barcelona, the prizes will come.