I've not properly raided on resto shaman but if you look at the logs there are a few problems that could help them improve. The shaman shouldn't just get a free pass because 'shaman are poor just now'.
The shaman has talented into Unleashed Fury but only cast Unleashed Life 15 times on the Iron Qon kill, a 10min 51sec fight. The spell only has a 15 sec cooldown so should see a lot more usage and is a waste of that last talent point tier. Earth shield uptime was 80%, should this not be higher too?
1 ascendance used, they could've had 3 easily. I dunno how many times healing tide was used but doesn't look like enough total healing for 3 uses either.
It's maybe unfair to analyse the shaman just because they are bottom though. Look at the druid, 80% lifebloom uptime and only 21 swiftmend casts too so it's not just the shaman that could be doing better. Looks like tranquility was only used once too, didn't use barkskin, only used Ironbark twice. It's just easier to look good on meters as a druid since all the hots are fire and forget but I think you'd need to look into more detail than just HPS.
This looks like a good guide on WoL for looking at healers. Not read it all yet though.
http://www.cannotbetamed.com/resourc...-world-of-logs