I agree that there are many professional and other high level players using, at least as a platform, the same "tweeners" that are available to the masses at retail. In my opinion, their successful use of these frames is primarily due to the following three factors:
1) They grew up playing with "tweener" racquets so their strokes were developed and fine-tuned using same;
2) Customization (re: weight/balance) and, in many cases, very frequent stringing at optimum tensions for their games; and
3) Skill, practice (practice, practice, ...), physical and mental conditioning, etc.
Not to say that you, personally, shouldn't continue to use a heavy, thinner-beamed, smaller head frame - if that is what you are most comfortable playing with. I can guarantee you that most (if not all) of the players at the upper tier of the sport can play a pretty respectable game with just any frame in their hands but, instead, they use what works best for them - whether its Fed with his 90-square-inch-more-traditional model or Nadal with his 100-square-inch-higher-tech job. The bottom line, however, is that anyone, at any level, can successfully use one of these "rocket launchers" if they actually take the time to work with it until they find the right fit or set-up.
