If you think they only raid those times then you're terribly wrong haha.
I hope you're not comparing Scrubbusters with a regular top 700 guild. They're #8, that's the top of the top and they have somewhat "casual" raiding times. If you were to see how many of the top 25 guilds that raid LESS than Scrubbusters, you'd probably find... zero.
I'm fairly certain that if Scrubbusters doubled or tripled their time to get to the level of the other top 10 teams, then they'd be able to compete for the first spot, but they're not super hardcore, they're just very very skilled. At least from my perspective.
If that was the cause he wouldn't be the boss with the realm first or immortal achievement. And when you consider the fight as it was intended to be it obviously was attempting to be more challenging than Lei Shen. The 'optional' tag was just an excuse for not putting it into LFR. Do you really think the forums could take the end boss of an instance kept exclusively to heroic in the current game?
Exactly what I was going to say. We didn't even get to do the boss as intended. But at the same time Lei shen did give the title and cutting edge, not Ra-den. It's sort of weird how they split the end tier achievements and realm first between the two.
Also to OP. Next time do it when your group is average 528 item level.