Yeah. I totally agree. Jehan is the current lead developer of GIMP; together with Aryeom (a painter by trade) they are the mainteners of the ZeMarmot project, which is a 2D animation free movie.
(EDITED)
The entire problem you are describing here is fixed in upcoming v3.0. Vignette gets applied as a layer effect you can tweak at any time later. No need to create extra layers.
By the way, the “features nobody uses” in that particular submenu include “Drop Shadow”. So I don’t think your summary is anywhere near correct.
Besides, you can search for a filter you need. Just press / and start typing. Many larger apps have a search function now, that list includes Photoshop.