We've been trying to get one of our guild members a legendary staff from Firelands on our off-raiding night, which is actually quite a long slog.
You'd think it'd be an easy raid for a guild in heroic DS - and for the most part, it is - but Ragnaros actually gives us more trouble than regular progression content, to the point where we almost always finish at Domo.
We also tried heroic Shannox once or twice tonight for fun; it wasn't pretty. It's a little difficult to catch Face Rage when the only shot that works for me is Chimera and the other ranged don't have great shots either (we unfortunately don't run with a mage/warlock regularly). Saving Chimera for Face Rage doesn't quite work when you're the one getting swiped, funnily enough....
I'm starting to wonder if Firelands might not be more difficult now that DS is progressively getting nerfed - even if it isn't, it certainly feels that way sometimes!