Correction, it doesn't work to wake up from sleep indeed, sorry. I guess I experienced a few cases where I came back to the keyboard right after the display turned off, and since it was just after upgrading to 10.7.1 I jumped to the conclusion that it was fixed. Still requires a click when it went to sleep indeed.
I can understand how it would be a desired feature for mouse users, but on an MBP that's on the power adapter with no mouse, having to click the touchpad (something that you might never need otherwise) feels slightly annoying. I don't suppose there's a workaround for that, except of course disabling the sleep mode.