I remember a while back about the winner of a speed/economy run with a given amount of "GAS" and a specific engine size.
I'm talking about full size aircraft.
If I remember correctly, it was a glass slipper sailplane converted to power and the finish was dull or sanded with fine sandpaper. The idea is that "air" slides on "air" better than anything else. Howard/Brett, correct me on this if I'm wrong please.
Maybe we don't want our ships to "slide" better especially on the down hill portion of a maneuver?
We have shiny finishes because we want to win stunt contests!
Aerodynamically it's probably NOT what we want, in many cases it has appeared that the flow was laminar until something disturbed it, leading to radical changes in the performance at near-random. Getting rain on the wing, for instance.
Turbulators, vortex generators, etc. are all more-or-less intended to stir everything up on an otherwise smooth wing so the flow doesn't change drastically. In either case it may or may not improve the lift capability, drag, or L/D but that's not nearly as important, and in particular, drag can be your friend (as you note). The wing on the Infinity is not ~2 3/4" thick at the root just to get more lift...
Brett