I don't know if anyone is having stuttering problems with the farcry4 editor, but I hope they fix this. This is not funny no more , farcry3 had the same problem,
Not got any shuddering in my game (XB1) I do how ever get the odd kaleidoscope effect when in the editor. (Fixes itself if you press start or move about)
Note:
If you're only taking about when painting textures or vegetation specifically, then yes I get shuddering.