spaceman_spiff
Hall of Fame
How about doing a James Blake and swinging a frying pan at 100mph :mrgreen:...
On topic: As always it's about moderation. A heavier racquet does require more of a set up, which can result in late shots, plus the faster swing of the lighter racquets aids in the generation of spin giving you more margin. But a heavier racquet gives slightly more free power on a slow swing, and is more stable outside the sweetspot. You need the racquet you can consistently hit nicely with.
However, when you do get a nice shot you want to be able to hit it as cleanly and powerfully as possible right?
A faster swing gives you more topspin and more margin for error if, and only if, you get the timing right. In practice, people who try to use very fast swings often get the timing wrong and miss the sweetspot (often framing the ball) or miss their target by quite a bit. Timing a fast swing is difficult, especially if you're on the move or dealing with heavy spin.
On the other hand, a moderate swing, although it only gives a moderate amount of topspin, is easier to time correctly and gives you more margin for error if you get the timing slightly wrong. That's because you have more time during the swing to make minor corrections with your wrist and the racquet spends more time in the hitting zone.
If you take a frame that has a large sweetspot and consistent string bed (due to a hefty swing weight) and combine that with smooth, moderate swings, then you'll get more consistent results than you would with a lighter setup and fast, whippy swings. You'll also get better results on shots where you can't use fast swings, like volleys, defensive shots, and blocked returns.
So, if you're hitting good rally balls, returns, and defensive shots more consistently, then you should set yourself up with more chances to go for aggressive shots like approaches and winners. And when you get those chances, you should have enough time to prepare early and swing as fast as you need to in order to get the power that you want.