Numbchux, I can't thank you enough. This is exactly the kind of big picture insight I was hoping for, very, very helpful to me. I just got back from driving a craigslist 2001 EJ251 4AT with 270,000 miles, it needed work but it drove well and it was dirt cheap, didn't buy it because with an AT I want an H6. Gave me a new appreciation for these older Gen 2 OBs (and I'm not biased, my Toyota DD is 37 years old with 409,000 miles).
I have been overthinking this, but that's easy to do with an unfamiliar vehicle, I have a Black Belt in my DD but Subies are new to me. For many years I have wanted a silky smooth 6-cyl car, in part because my DD sometimes vibrates so much I need a kidney belt and I have had enough vibration to last me several lifetimes... always thought that would be a V6 until I heard about the Subaru boxer engines... my intended use is light offroading (forest roads, occasional bumpier stuff) while exploring and dispersed camping off pavement... Sierra Nevada, Colorado Rockies, maybe up into Canada... lots of freeway miles where noise and comfort makes all the difference over many hours. So the H6 appeals strongly. Though when my friend gave me a ride one time in her H4 I couldn't believe it wasn't a V6 it was so smooth. I'm an MT guy but I'm thinking it wouldn't hurt to consider a 4AT for the softroading part, especially considering that when I go on an exploring roadtrip in the current MT DD I shift into 5th and stay there for hours on the freeway anyway. The posts about a failed AT meaning the end of the car kinda ruined that, but you have turned that around with your post about the availability of good used ATs.
And I agree about the 2005+ CANbus cars. As a network engineer, this is like depending on an eggshell to keep the car running. Too many essential functions depending on a single point of failure.