I have used the class listview-stylingless to remove all styling. BTW, this class is also available for all other data objects (dataviews, template grids, data grids).
I also made noStyle and noHover classes to overwrite the lined style.
No biggy in my opinion, it has to have some default style...
you can add predefined classes to listviews, see:
-> Design elements -> Data Grids
Maybe a helpfull addition: in the Sass folder you can find the file _listview.scss. By editting the styling of the listview here it should overrule the default and use it as your own new default for listviews:)