I have no problem setting and using my assist. I can see (if I bother to look) what my assist is targetting because I have party target windows on...and sometimes mt targets are on and my assist is on there too. Problem is, I don't bother too look. I'm too busy strafing/lookingatcombopoints/tryingnottodie/rooting/cycloning/havingabiteofasandwich/etc.
So when my assist changes target it would just be real handy to have a 'ding' or something :X