I'm never surprised by what my pokemon use with Metronome because the point of the attack is to have a random result; so I have an equal chance of having an attack that suits the pokemon as I do of having one that doesn't.
However, without much exaggeration, on all of my games I've often wondered if I have a problem where, instead of Metronome having a 100% chance of a randomized attack, it has only a 10% chance of a randomized attack and a 90% chance of using Crabhammer. I can almost depend on my Metronome being Crabhammer attack; when I want to use it I actually plan around it; it happens that frequently. Don't get me wrong; it's a strong, solid, useful attack, but I'd kind of like Metronome to serve its purpose every once and a while o_O