I think it would have been better for Bayern if they had parted ways with Tuchel immediately instead of keeping him until the end of the season. To be honest, if you look on Bayern Munich's performance in the last few games, I see Arsenal as the clear favorite in the CL. Somehow I also have the feeling that Tuchel isn't taking it all that seriously anymore. Dortmund were well prepared today and Arsenal will definitely prepare just as well.
Easier said than done. I agree that Tuchel wasn't the right choice especially since he is so similar to Nagelsmann in terms of how they coach a team. This isn't meant to say that Nagelsmann and Tuchel are the same level, but they are very similar character in terms of their approaches as coaches. Since Bayern wanted this surprising and massive change during a solid season from Nagelsmann to Tuchel, I think most of us were shocked because it wasn't really a fundamental change.
But now looking back it would have made sense to fire Tuchel earlier as his responses to defeats and criticism were pretty weird sometimes. He was talking weird trash in interviews. It would be rough for Tuchel if they get Nagelsmann back now! But the problem for Bayern was that they had to have an alternative if they fired Tuchel and there weren't really any good coaches available who were also willing to spontaneously jump in I guess.