Different Size Columns
Provide the option of having unequal column sizes, to provide a 2-1 ratio. This would give easier sidebar style layouts.
Steve Jenks commented
Yes, this would be very useful. The ability to set up a text box with multiple columns, with the ability to either manually drag the guides to make the columns different sizes, or the ability to enter a width and have the remaining columns adjust accordingly.
Oleh Melnyk commented
Go to View > Grid & Guides > Lock Column Guides (enabled by default) - once disable you would be able to manually change columns with a mouse
make a 5 column grid and use 2-1
Scott Falkner commented
You can adjust column guides manually. You can't have different sized columns in a multi-column text frame. From your request it looks like the former is the solution you want.