Kompany is new to the business but that doesn't mean he can't be up to the level of coaches like Pep Guardiola, Ancelotti or even Mourinho, he has made some mistakes but he's still on track to me. And for Kompany to last long as the manager of Bayern Munich I think winning the champions league will give him full ground at Bayern. For some coaches that started with with him like Lampard and Rooney (as ex footballers) I think Kompany is the best among them all, he just need to give the club something they have lost and that's the glory of Bundesliga, getting them that trophy is going to be a big win for him and I don't see the management sacking him.
As time goes by, his ability to coach a team will increase, and Bayern Munich is the place for Kompany to realize that, it is possible that in the future he will become a successful coach because if assessed, his current career with Bayern Munich is quite successful even though he has just become a coach. Regarding trophies, I think a realistic target for him is to get the Bundesliga title this season, that is enough for Kompany for now in improving his career.
Kompany has potentials all he needs is time to blend with his current role at Bayern. Predicting him winning the current championship league is way too much to expect I no he will definitely see how he is progressing with the team currently. On average he is not up to 1.5 years in his career which is barely 3years overall and he is doing this good then imagine what will happen if he has built enough experience over time.
I believe no one knows it all. It takes experimenting, trial and error, persistency and confidence to build a formidable team which I see the potential In kompany.