Skill speed actually comes in Handy with the following classes
Warrior: They need a certain amount to fit 5 Fell cleaves
Dark Knight: Needs a certain amount to fit 5 Bloodspiller in Delirium window
I believe it helps Dragoon, Monk, Sam as well. Bard I'm not too sure about. I wouldn't go insane on the skill speed but I would at least make sure you have some of it. I was really hoping that other Materia would be good to use but it's still the same Crit, Direct hit, Determination meta still. I do see some Skill speed melds out there so it just depends.