Larry makes a good point. There is very little correlation between how well folks play and how well they know their chord theory, with the possible exception of jazz guitarists. Over the years, I've played with hundreds of other guitarists, some beginners and some extremely good players. There were folks that knew very little about chord theory that were absolutely wonderful and even complex players, and folks that knew a lot of that but could barely play.
Interestingly enough, my wife, when I met her, had just recently obtained a bachelor's degree in classical guitar performance. She could play just about anything written down pretty much right off the page, but she couldn't tell you whether she was in E minor or B flat major. Of course, my influence has now "tainted" her and she plays all kinds of different music and knows a great deal about chord theory now.
