Q:

Wake sleeping screen with mouse move not click? 

Prior to Lion I believe moving the mouse woke a sleeping(powersave) screen, and now in Lion you have to click.  Often I am in the situation where I am about to go to bed and want to sleep my imac, but am unsure whether the machine is already fully asleep or just the screen.  Previously I would simply move the mouse to find out.  Now I have to click, which means I wake the machine either way i.e. if it was already off, and then have to shut it down straight after. 
Is it possible to bring back waking power saving screen with mouse move? 

A:

I believe the wake on click issue has more to do with the pointing devices shipping with the preponderance of new Mac systems: wireless keyboards, mice or trackpads for desktops and laptops. 
There are two potential reasons for a click:

To maximize battery power, wireless keyboards, mice and trackpads power down when not in use--just like computers.  
Today's mice are all optical (laser or otherwise) and they turn off the light sources when asleep.  The device does not register a movement until awakened.  Wired mice might still wake a computer on movement. 

I also don't believe the computer sees a difference when "waking" from any of the low power states available to it, be it a dimmed screen, a screen in lowest power state, or the computer "sleeping".  A device "click" initiates full power mode.