As is when making a test case that required ordered output, if a change needs to be made then every test case after has be copied and pasted and re-entered in order, making small changes take much longer. Some way to easily reorder keywords would be a huge usability improvement.
Click and drag would be the most intuitive.
A numbered list would also work, where one could edit the number to indicate where an item should go in the list, bumping all other items down one.