In my experience pokes don't need to have perfect values to be viable online, as long as some thought has been put into the team building and moveset (the actual fun stuff

). Natures and EVs do make a big difference though. It's actually kinda fun to try something different to the standard sets, or use pokes that aren't used much.
I remember reading an article where someone used an eviolite Scyther and got kinda creative with the EVs, and it was a pretty unique team. I think it was on Nugget Bridge.