Since ages, I have installed both, BC1 and B22. I mainly use BC1, BC2 is only for reminders (because BC1 has a long existing bug with adding notifications).

Whatever: the only thing that makes me keep BC1 is that it just looks better, especially the rounded boxes in the weekly view and the colors.
I found a request added here 5 yeas ago ("Possibility to use BC1 theme in BC2"), with exactly the same thoughts. This was rejected without explanation and I wonder why.

Is it that hard to just create a theme in BC2 with colors and corners to make it look like BC1? I guess this would suit a lot of customers.