It has been always annoying me that I could not select more than one column in the Excel Text Import Wizard / Assistant.
I had to select single columns in a preview window and then set a fields data type one by one even if all fields were of the same data type.
Using the Shift key you are able to work around this bug in the text import assistant.
Select the first column then press and hold shift key down and select a column to the right or left of the before selected column.
All columns in between the two selected will be selected as well and are available for property editing :0).