In the galciv2\gfx\weapons folder are the actual weapon effect files, editable via notepad. Unfortunately, they don't seem as straightforward to mod as the xml files.
I'll look around for a guide for editing the wfx.x files, and see if there is a way for decreasing the actual number of frames for each animation (deleting, say, every other frame). Increasing the rate at which the frames cycle would work too, though I imagine that would be more complicated.
