Perhaps "limited" is the wrong term. It is not limited in what you can do, it is limited in what is defined by the rules. Since everything that is not defined by the rules has to be decided on by a referee, then the referee has to spend far too much time for my taste making rule decisions, and not enough time (again, for my taste) working on the actual plot. Of course, OD&D wasn't originally envisioned to be played with a plot: it was (from what I know about it) a slightly expanded dungeon-crawling wargame.
I do not doubt that you can have a rich role-playing experience with OD&D. I do, however, doubt that the vast majority of DMs could pull that off. If Crothian can, hats off to him. Note that you mentioned games that have been running for 30+ years. Undoubtedly, referees of those games have long ago made critical rules decisions and house-ruled most (if not all) rules issues that could pop up in a game. Thus, they are now free to focus on creating interesting stories and making up kick-ass dungeons. A person new to the system has a bumpy road ahead when he has to work out all those issues for himself.
As stated earlier, I have no interest in running or playing in games that rely on ad-hoc decisions. I do not believe in the mythical "trust" between the GM and players, since I am a GM myself and I can be right-down rat-bastardly if I feel like it. Additionally, I spend at least 12 hours prepping for each of my 4-6 hour sessions, and most of that time is spent on the plot and NPCs. Using an ad-hoc system would mean that some of that time would have to be spent on house-ruling, which would detract from the rest of the experience. All this has nothing to do with my experience with role-playing systems (as implied by Ghendar), since I have experience with AD&D 1st and 2nd edition, RIFTS, Warhammer FRP, Vampire, and so on. Codified rules are what works for me. My initial concern was about Crothian's players, but if they're fine with it, more power to him.