According to the Sony press release linked, dumping rumble support allowed the hardware manufacturer to incorporate a "six-axis sensing system" for "X-Y-Z, pitch, roll, yaw, and lateral motion detection" into its new controllers, as the vibration purportedly interfered with the new motion sensor. Adding Bluetooth wireless connectivity and rechargeable batteries charged by USB made up some, but not all, of the lost electronic innards, as the new control pad now weighs less than its PS2 predecessor.
We can't help but wonder whether even a smidgen of this loss of controller functionality was prompted by the ongoing force-feedback patent lawsuit from Immersion or not. Whatever the case may be (and however the court case turns out), we are fascinated with the old-school update to the standard bundled PS3 controller -- and how well the new interface adopts the best features of the Wii-mote and the 360 pad (including that branded Guide-like button smack in the middle of the thing). The L2 and R2 shoulder buttons resemble analog triggers even more now that they appear to jut out further from the hard controller casing. Could we have the beginnings of 360-style shoulder buttons here? Hopefully we'll have more to report on these possibilities and more before the end of the week.