I wonder why they wouldn't upgrade the 60mm saw to cordless, rather than busting out another revision of the 55. I'm skeptical of the one battery solution -- one of the incredible things about the TSC55 is how the two battery platform matches or even exceeds the power of the corded model, especially near max cutting depth. Perhaps the new battery model is able to make up the difference?
One of the reasons I've stayed away from the cordless Mafell MT55 is because it only operates with a single battery.