no simple way to do that, I'm afraid
a couple of things that could help:
1. turn on clip keyframes.
this is the tiny button bottom left of timeline with blue & green lines
click that and an area opens up underneath your clips with blue & green indicators
blue is for motion and/or speed effects
green indicates a filter.
so you can at least see which clips have filters
if they all do that's not much help!
2. jump from clip to clip in the viewer.
double click the first clip into the viewer, go to the filters tab.
now when you hit the up arrow you will jump to the next clip on that track, and remain in the filters tab,
so you can fairly quickly scan what filters are in each clip
it helps if you;re clips are on as few tracks as possible.
"in the inspector the old plug in was still listed, but could not open the control "
inspector ? are you talking about FCPX?
sorry, i doubt anyone here knows that.
nick