This is really the only thing I miss from FPP.
It had a hue effect for hotspots/plugins which altered the hue.
This essentially means I can adjust my entire skin theme in xml, as it is now, I have to alter each and every graphic manually in photoshop.
That's a major pain.
There are probably other nice effects that flash supports that would be good as well. Saturation, etc.
And damn, this would need to be possible in html5 to be useful.
I don't know if you can adjust image hues in html5 for images.
There's something called hsl color module