There are just two possible reasons to put paint with a design on an aircraft:
a) giving an attractive look that help business in one way or another.
b) It is cheaper.
Either it is attractive, and people disliking it just have their taste out of whack, or it saves LH money.
In my opinion there is absolutely no reason why it shouldn't be possible to combine both of the aims cited above.
There is no "either...or", if it's done in the right way, there can be a "...as well as...".
2. Why no yellow? I talked to a lot of people here in germany, all of them no airline/plane enthusiasts.And all of them told me that for them the signature color of LH was yellow. (...)
With the new livery they have given up their signature color. Even if only the crane and circle around it would have stayed yellow that would have been enough.
Yes indeed. Somebody had posted this image at the beginning of the year when the discussion had started:https://www.airliners.net/forum/viewtopic.php?f=3&t=1375315&start=700#p20145583
Reduce the size of the circle and the crane, so that the whole circle fits into the vertical stabilizer and it would be a pretty superb livery.
But since Carsten Spohr has decided to drop the yellow at all costs, because Ryanair uses yellow on a blue tailfin, this won't happen, at least as long as the current CEO is in office, because it would mean to admit to have made a mistake, so they will continue to get rid of the yellow, because white is soooo minimalistic and it sends a feeling of PREMIUM towards anyone watching it...