I know that you can have multiple flow conditions in "Advanced mode" although I dont think this should be required to do this to have 2 conditions. Seems a bit clunky to me.
My suggestion would be to have the ability to add another line to the basic mode. with an "AN" or "OR" between them. The you are able to use the basic editor to use the dropdown to add another condition. This is how it works in Nintex workflow and I love it. Also it would be great to have the advanced mode Popup a new window with all the functions and a multiline text box.