It's true that Barcelona are better than last season, even so, I think Bayer will be much better. I don't see them humiliating Barcelona like they did last year, but they should win.
Barcelona and Inter will fight for the second place in the group, when the first will come from Bayer.
Bayern regularly beat Barcelona even during Barcelona's golden years. Barcelona is ball control, one plan A, and Bayern is the same perfect ball control + smart football in terms of changing the game rhythm, deliberately giving the initiative to the opponent, that is, several variations of the game at once. I would hope that Bayern and Inter will advance from the group to the next round, but in fact any combination can turn out - even for Bayern there is no guaranteed ticket to the playoffs.