Rork is right though that he's playing like he's in a 25 man environment and not the 10 he actually is in.
I am playing 25 man and I use riptide on things that take dmg UE HR on cd, keep HTT on cd at burst Alternate SLT, HTT , HST , PE fire and earth and ascendancy for bursts (epicenter, total annihilation elegon) and fill with CH/HW depending on packing since its 25. Replace CH with HW all the time hasted from tidal waves for 10 keeping ES up. Shamans are in a good place both mana and throughput so the amount he's doing is as Rork states a simple l2p issue.
Can someone raiding 25 playing 12.5% haste(871) and stacking crit link me a log of say feng or elegon. I've been playing 3764 haste since mop release then floating around 50% mastery kinda not fussing over crit that much and I still get a fair whack back from my 8% crit from resurgence would love to see how much more mana they get just from that excluding TC,WS glyph, mtt and price of progress.