This video shows the delay of charge stun caused by update time pretty well:
Here the stun is applied only when the warrior reaches his target
https://www.youtube.com/watch?v=NETLBN2L8jM&t=4m18s
Here the stun occurs almost immediately
https://www.youtube.com/watch?v=NETLBN2L8jM&t=6m53s
Before 4.3.0, charge did not take into account that characters were moving afaik:
I believe that in Cataclysm, the delay on abilities was also reduced from 400 ms windows to around 10 ms. If everything that you say is true, I assume that the Charge update that you're referring to must've been implemented to compensate for the change in latency so that the end-result of using Charge would generally be the same as before.
Something has to be done to give us a proper result from using Charge abilities if we're going to have Cataclysm-like spell delay.