"Hopefully, I am not just trading numerous known design flaws for quality of repair/install issues."
You are a wise man to know this is true. I put off doing the upgrades for years as I know when you tear apart something very complicated like these vans, you may fix the issues you had trouble with, but you may create other issues, large or small, that can make just as much trouble for you. My oil pressure leak was a small leak at a plumbing fitting that cost me my years vacation and a $1,000, mostly in labor. It was just a tiny leak... Sigh.
If there was one thing I could add to my van it would be an "Override" function, so that no matter what was wrong, you could hit Override and at least drive it. All those sensors and computer functions protect the engine, but can leave the human stranded.
Good luck! Hopefully we'll be out on the road together again!