I've been playing for many years and have most of the titles, though not all. I missed this thread a month ago and just saw it now. I agree the games are good, though with issues that don't need to be rehashed here.
they were mediocre but released a big AI upgrade last year that made them great.
Are you talking about the engine 4 upgrade? If so I think calling it a big AI upgrade is a bit much, and in my opinion it barely moved the needle, let alone made a mediocre game in to a great one. AI is one of Combat Mission's biggest weaknesses in my view. The TacAI works OK, but things are mostly handled through scripting.
The main points of the engine 4 upgrade are:
-- Added hulldown command
-- Improved infantry spacing
-- Added ability to peek around corners (which really wasn't needed and introduced other problems, particularly with pathing)
-- F/O kill stats now displayed
-- Added screen edge pan toggle
-- AI Area Fire Orders (The AI can now be scripted to use area fire)
-- Added AI facing order
-- Added AI withdrawal order.
So really, the extent of the 'big AI upgrade' was making troops spread out more and adding a couple of new orders in the UI