Two things I've found in my experience - your mileage may vary:
1) Swingweights are too often misleading and occasionally just plain wrong. I recommend that everyone who cares about the spec's of their racquets should get familiar with their preferred static weight and balance. My opinion of SW's is that they're some sort of gimmick that some "suit" came up with to help sell more racquets. I'm happy for anyone who has had good luck with this handy-dandy reference, but I think it has caused too much confusion among players. If you know the static weight and balance that you like in a racquet, you'll know at a glance whether a potential demo, etc. will feel familiar when you use it.
2) Maneuverability in my racquets absolutely comes down to the right balance. My 12.8 oz. ProStaffs have a balance of around 10 points HL. Although they're rather hefty, they are also very easy for me to handle around the net. In contrast, when I got a pair of LM Prestige mids a while ago, I was helpless with these lighter frames, especially around the net, because they were only a couple of points HL. After putting a bundle of lead tape on their handles and taking their static weights up to 13.4 oz., I was much more comfortable with these racquets because of their balance.
I will note that while a stiff, light racquet would probably be quicker for me around the net, I'm also hooked on the stability that comes with more heft in a frame. Although my trusty ol' 6.1 Classics aren't as lightning quick as some fly swatters, I only need to get these racquets behind the ball and use a minimal effort to pop it back over the net. Where a super light frame would get blown out of my hands in some heavier exchanges, these racquets are rock-solid.
So that's just me...