Terquem:
You are not the only person going through the issue of trying to absorb the new rules. I have been playing since 1981 and have been involved with making games since 1987. I was an expert playing 1st edition AD&D. I could pretty much open up the book to the exact page by feel. I knew where everything was and those books had horrible organization. But that didn't matter, because I KNEW them.
Flash forward 30 years and I am as befuddled as you are looking through the various rules forums. It IS like a foreign language. There are so many feats and archetypes and such that it is many times a bunch of blah, blah, blah, blah to me. And I OWN the company and the game! :)
But I don't let that stop me. I run a weekly game where one of my players was heavily involved with creating the 3rd edition rules at WotC. He knows them backwards and forwards. He calls me out on my mistakes from time to time. I just roll with it. Sometimes it is great because I can just ask him what a rule says and he can tell me without me having to look it up. Sometimes it stinks, because I disagree with a rule. But the good news is that my players go along with whatever my ruling is and we move onward. Sometimes I use the old trick where I say something like, "You are right, usually you can't do that, but this guy can for some reason" or "This version of that magic item works slightly differently than the ones you find commonly in the streets of Absalom."
Basically, I am willing to wing it and not be an expert on the rules. I've decided long ago to put more ranks into roleplaying and knowing how to run a campaign that is fun and has people coming back for years and years than into things like Know Rules. I just don't care about the rules enough to warrant that kind of expertise. Also, that is why I have folks like Jason Bulmahn on staff.
In closing, I can understand feeling that the game is moving away from you at a fast pace. Us older folks (and I AM older than you by a little bit) don't adapt as well as we used to when we were young. But we can still have a heck of a lot of fun roleplaying by just not taking the rules too seriously and enjoying roleplaying with our friends. That is what it is all about afterall.
Glad to see that you aren't giving up! There are a lot of kindred spirits here on the boards. Hopefully you can find a new group of friends here and will eventually jump back in the GM seat.
-Lisa