AI Traffic, Realtime traffic and ATC really request huge improvement… as many other areas in MSFS. During Dev Live Q/A it’s almost been addressed by the community asking for news. Weeks ago, I remember Asobo mentionned they want to rebuild anything from scratch as the old FSx need to get more than revamped. But during the last Dev Q/A, Mathias mentionned optimisation and fix are still on theirs ways. Maybe I mix all up between ATC, AI traffic, realtime live traffic…
At the end of the day, it’s going to be a matter of priority.
Same here. Except that sometimes, I love bringing my small Cessna to international airport searching for cheap FBO’s 
Back to smalll GA traffic, you certainly know AIG and a sort of trick to have airliners + small GA traffic at the same time. If it’s a discovery for you, look at this thread: Adding GA flights with AIG traffic - #7 by PhantomStreak