This is very interesting to hear - Hear hear .... I have been wanting and hoping to replace my older Duo's with newer Trio's (preferred) or Duo Mezzo for some time - just looking for the right deal on a used pair. From what I think I'm hearing you say, you don't find the gap from old to new Duo's that large. I wonder if you would mind elaborating a bit more?
The trios with bass horns are a massive upgrade over duos Marslo has now bought trios, his duo mezzo XD are now on sale. When I had visited the AG factory (three, four years ago) Armin's preference there was also clear. You can listen to all their speakers there. It isn't even close.