It's interesting to watch how RPG discussions have evolved online. I remember back in the late 90s, and the early part of this decade, people would go on and on about games, but you rarely saw actual play reports or discussions. Say what you will about the Forge, but the focus some designers there brought to actual play and in-game experience has really changed things.
All too often, designers who don't play their games tilt at windmills. People get all worked up about, say, classes and levels, but when you sit down to play D&D the "problems" they pose never materialize.
A game designer who doesn't play games is like an alien with a perfect command of English but zero cultural knowledge. Sure, he knows the words, but he doesn't speak the language.