Ronster said:

I thought the dish should take down an AT-ST when we first saw their inclusion but some more pronounced effect on hitting an AT-AT leg would help it look better.

hm, would be nice to have this "mini-ion cannon" firing either first on the AT-AT leg, only to show sparks/ electric discharge, and later to hit an AT-ST, which then stops in motion and falling down ;-)

or it could be a "major-laser", burning the leg/knee part and after that (or before) destroy an AT-ST like in one of the Endor scenes ...