I won't decline for mouseovers as long as they show the actual URL of the site the surfer is going to. I've also never had any problems getting listed, and I always use them.
In fact, with a lot of sponsors their ref links look like
http://sites.sponsorname.com/wm=2345&site=304&pop=2 or something like that, and in those cases the mouseover gives the surfer a clearer idea of where they're going with sitename.com than the actual sponsor link.
The easy way to use mouseovers with DW and not type the damned thing every time is to use the exact same opening <a> tag including the href and mouseover, then just copy and paste that in the html. You can't do it with the WYSIWYG interface, but it's much quicker that way anyway.