I feel a lot of the talk about who should and who shouldn't play blades is a way for golfers to seperate themselves. I cant speak on the science behind it, but I have played both irons. When I was younger I played Pingeye2's and hit the ball well, but when I got to high school and became stronger I was frustrated by my inability to work the ball from left to right with my irons. I now play MP60's/ProjX, if you are new to blades I would urge you to check out Mizuno. The MP52's are a little more forgiving than the MP60s, but still great clubs. If you are not fimiliar with "Cut Muscle" check it out. Not quite a blade, but as close as you can get. I have hit most clubs on the market, and in my opinion Mizunos are butter. If I were wealthy I would play MP67's.
As far as what it takes to hit them well... Consistancy, you will notice the wear on the face of blade irons is usually in a concentrated region. This is because the player consistantly strikes the ball in the same part of the face. Not hitting the sweet spot will make for a poor shot with blade irons, cavity backs are designed to allow the player whos golf swing is inconsistant to use more of the face.
I apologize, I didnt address your question. Cavity backs were designed for golfers who do not hit blades well, so to hit a blade well but not a cavity back simply goes against popular belief. Not saying its impossible. Though consider the difference in the driver swing and that of the iron... Its even more important to use the tension built up in your torso to swing the club with an iron in hand, and not your arms. No need for 118 swing speed in the fairway.