It seems like this latest major change has caused voting to appear to be slower. Several times I've voted for a comment in a story and it took so long to change that I clicked the button again, which reverted my vote by mistake.
I would like to suggest that changing the icon immediately and then processing the vote might be better. Something like a spinner or even just graying out the vote icon would inform the user that the system has started processing the vote but it hadn't finished yet.