Critical

Now that you mention it, I don't believe I've seen Shock crit either. I looked through the other skill pages on the wiki, and it seems like the only other skill like that is Life Drain. Also, iDSd, the distinction between dealing critical hits and dealing critical damage is at least a little significant. For instance, the skills Info listed above would probably still train Critical Hit while Shock would not. Of course, if you're still training Critical Hit by the time you get Shock, you're probably doing something wrong, lol.