That’s unfortunate that inner blocks isn’t supported yet. Like you, I had to settle for WYSIWYG editors inside my columns.
For my column layout I went with a repeater and styled it for a horizontal layout. I widened the content area so there is more room to work inside each column. I also added a button group for different column layouts. For example there are 4 layouts for 3 columns, 5 for a 4 column layout, etc. Then I used JS to resize the column widths based on which layout was selected.
Overall it works nicely.
