I think you're fundamentally misunderstanding the architecture, capabilities and relationships between observable and observablehq. Not having a button next to each cell to edit it in place, is not going to impact your productivity in any way, when you can just edit the cell in the window to the left. Wether it's below or left isn't a meaningful difference, and shouldn't have an impact on wether or not it's a suitable replacement or superior/inferior to other notebooks.

Hope you'll look at it again in the future. In a sense it's your loss, so good luck and take care.