ISTR one of the reasons we didn't adopt the vortex generators was they are an admission that wing is designed wrong.
That's one of the reasons they show up on planes which entered service without them, they're fixes.. relatively inexpensive though.
Another thing we tried was the McDD "engine ears"' those vanes on the wing engines on the DC-10.
Although there was a benefit to the stall speed, it wasn't sufficient to warrant purchasing the license to use them.. and NIH (Not Invented Here)
MOF, when we tested them, we made them out of 1/2" Lexan, so they wouldn't be visible from the ground.
Interesting flow patterns off them at the stall...
I have some film footage around here someplace...