I guess I don't understand why you would disable CS given what you want from your device. It is designed to do exactly what you want. The computer may technically be 'asleep' but it wakes instantaneously so who cares? This is like saying you want the 'power' button on your phone to only turn the screen off. What's the point other than wasting battery?
Actually, the power button on my phone does exactly that. It shuts off the screen, but the device is fully on and not in a sleep or standby mode.
When I did have connected standby enabled on my SP3, it would go into sleep mode and take like 10-20 seconds to "boot" back up. I hardly call that fast and instant. I do not need the actual features of connected standby since I don't need my weather apps or whatever updated, but I just don't want the SP3 to be off.