This. This fly exactly, in this size, for those reasons.
I was thinking this before I even got to Steve's response.
Probably in yellow/orange coloration, but any combination of yellow, orange, green, olive, black, red, peacock, grey, or red will do.
It works in no hatch, as stones, caddis, hoppers, fluttering mayflies of any type in any size within one of the chosen fly, and I've even used it as an impromptu wet fly, to swing past a fish.
It's also highly visible to the angler, in any condition, and will float without a big ugly footprint on slow pools, but won't get drowned by any water you can wade through.