The Boulevard C50 is the exact same bike as the Intruder Volusia 800, which consistantly is rated the top bike in its catagory, only now with fuel injection. It was never meant to be a muscle bike, is is a custom cruiser, intentionally heavy to make the bike feel and ride more like a larger displacement cruiser. It is not only Suzuki's best selling cruiser, but the best selling cruiser in its class overall, so why on Earth would they change it? It is a great bike and they sell every one they make. It's just not what you are looking for if performance is more important than comfort and that classic custom style. Personally, I dislike ALL bikes with that fat-boy look, and ride a slender, chopper-like VS800 that will run circles around the Volusia and even the 1500 LC.
If you want a faster bike instead of a big, fat, custom cruiser, try the venerable Intruder VS 800 (now the Boulevard S50), which in last month's test proved to still be the fastest and best cornering mid-sized cruiser on the market.
Or the new Boulevard M50, an all-new fuel injected muscle bike due out in December.
There will also be a 1700+cc version of it, the Boulevard M105, due out in about a year. Both are more of the lightweight, performance before comfort bike you sound like you want.
Suzuki has neglected their cruiser line for many years while they pushed for market share in the sport bike, four-wheeler, and scooter markets, but they are on the right track. That horrable Maurader 1600 died after just one year, and one new model will role out a year for the next 5-7 years, starting with the muscle cruisers you crave.