I agree with most of your post, but I take issue with this statement and definition. I'm not saying you did this in your post, but people use the term "sidegrade" a lot to denigrate gear from VW (or Legion). But I don't think they mean what they say. To me, "sidegrade" connotes a piece where you can essentially get most or all of the benefits of the piece from preexisting gear. A perfect example to me is the new Iaso Boots for WHM, a piece that combines 4% cure potency and 12% movement speed. You can achieve capped cure potency from other pieces, and you can achieve 12% movement speed from Herald's Gaiters. Thus, the Iaso Boots are a "sidegrade". Nice if you have them but replicated by other gear setups (well, we don't know its augments I guess, but still!).
You say VW gear gives you a small % of an increase. To me, that isn't a sidegrade. That is a piece that replaces other pieces in a gear setup because it does represent an increase, however small. If you meant that Abyssea gear clearly gives you more bang for your buck than VW, of course I agree with you. But I think people should be more precise. VW gear may not confer as much of an increase as Abyssea gear, but it contains pieces that are clearly "best" for certain functions.