I regret Airac that to me your comments still seem to be based upon a total misunderstanding.
The only time that I can comfortably accept flying in what you regard as a "totally known environment" is the occasions when I'm flying A-B on a known and pre-planned route. The rest of the time I am constantly manoeuvering, changing height, changing my mind, sometimes very low level. The burden upon RT of the amount of GA traffic remaining "totally known" during such flying would bring the whole thing to a halt.
The reality is that expanding controlled airspace for a minimal amount of instrument traffic serves to make life a lot easier for ATC, very slightly more expensive for a very small amount of commercial traffic (who will simply pass the costs onto their customers anyhow), and extremely difficult for a large amount of GA, many of whom are paying for their own flying. Put bluntly, it's unsupportable from any neutral viewpoint; ATC are there to work with the available environment I'm afraid.
G