I absolutely think the 1e quote definition of "role" is more like the 4e "class role" rather than "acting role". Pretending to be your guy was always in there, of course, but the thespianic style came to the forefront, I believe, during the late 80's, if the bulletin board discussions and letters I remember from Dragon magazine are anything to go by. Older folks, you can correct me if I'm wrong.
I think there are multiple quotes on the Ask Gary Gygax thread where he ridicules this style, and remarks that it's just a game, and shouldn't be taken that seriously. Quotes from 1e will not support Blind Ogre's definition of role-playing experience. However, I'm willing to believe that Basic and possibly 2e (which I don't remember well) might.
That said, I think that Gary had his own style and wasn't always as tolerant as he could have been of other styles. I have no problem with capital-a-Acting, or beer-and-pretzels, or what have you.
Personally, I prefer other ideas, like awarding action points for doing something cool, rather than roleplaying XP. Now that you don't have to spend XP to make items and get resurrected, we have an opportunity to have all the players in the party level together more often: which means everyone sits down with the rulebooks and character sheets at the same time, rather than staggered, which means less time wasted while waiting for a guy to update his sheet.