Hmm, that's something that I originally thought of when I was writing the analysis. That's an interesting idea now that in 5th Gen, Gamefreak does not include Stealth Rock as a TM. Personally though, I feel that Forretress has Toxic Spikes and Spikes and is one of the few pokemon that can reliably utilize both. So it should use those two moves over Stealth Rock which is more widely spread. Though Forretress is a great user of Stealth Rock so I'll add it in.