The ASD can change up the game, especially if you're not prepared to deal with mechanised units attacking you. Personally, I either turn tanks off or set their introduction to be very late-game, since they'll be waiting for you in Meduna anyway.

Yeah, unfortunately you can't reliably tell how well HVT Strikes is working unless it's fully upgraded and you do a few battles with it on/off to compare. Fewer enemy medics is definitely one of the expected benefits though

This is pretty much how I want directives to feel - pick what you need for your current situation, and then swap out as you require. Glad to read that you're enjoying it!