This is a welcome step forward, as I have found the Columns block limited in use compared to page builders. You said that “WordPress core’s current implementation of the Columns block is so confusing that it is barely usable.” I have to agree!

Even with these changes, the block is still quite fiddly to manipulate, though. The ability to have variable width columns is nice but I wish it was possible to drag the column edge to adjust the width as well as use the slider.

Any idea when these features are coming to Core?