One thing that bothers me about it though it that when I work on each block, I need to select it from the dropdown and work on it in isolation from the rest of the blocks, which kind of drives me to lose context of the overall flow and patterns.
So while playing with Reason today, I thought about this alternative view, in which all the blocks are exposed on the timeline, and can be changed by visually modifying their lengths.
In addition, this is also make it super easy to copy parts from one block to another.
I quickly mocked it up just for better visualization

Curious to know what you think about this!
PS, as a bonus thought, I was also thinking that maybe this can also work directly in the main timeline, so it eliminate the need to go back and forth between two different modes. So all the editing happens in one place. Basically switching different section in the main timeline into blocks and modifying their lengths from there.