in discussion Characters and Cast / Characters » Sylar's Real Power
I believe you are correct. In a later episode he discovers he can absorb powers without wounding or killing his victims but abandons this approach in subsequent episodes and returns to slicing & dicing.
I'm sure some of it is for writers to keep that evil edge but I'm confident it has to fill his powers need to see how something "ticks" (pun intended) :>)
