Guilds continue to bring Shaman's to world first, the most cutting edge of progression that none of us will see People who are more progressed then myself show the class working Tons of people are continuing to make the spec work from normal to early heroics to Lei Shen Many Shamans are still brought for their contribution to their team. Maybe not stacked but still having at least 1 in 25s.The class is clearly terrible.
Last tier, yes, Shaman were brought to world first kills. However, the viability of the spec has been severely diminished since the start of 5.2
1. MTT was more needed in 5.2 progression because people didn't have legendary meta gems (or 550 ilvl through cloaks and item upgrades). The legendary meta has the value of about 3 Mana Tides used on cooldown, so the value of Shaman at MTT bots is significantly diminished. MTT was the main reason they were brought to world first kills in ToT, but it is not going to be enough in 5.4 by any stretch of the imagination.
2. HTT was one of the strongest and most flexible raid cooldowns pre-5.3. In 5.3, they buffed Tranquility, Revival and Divine Hymn by 240% in 25 man raids, but left HTT out based on the ridiculous semantics of it being a talent and not baseline. SLT was and is a mediocre raid cooldown. Shaman went from having one of the strongest raid cooldowns to having the weakest raid cooldown of any healer.
3. Shaman throughput (post hotfix a couple of weeks into the tier) was low but acceptable in 5.2. It is now ~30% behind in 5.3. If SoO mechanics are any indication (far less stacking and more spread and movement than ToT), it will be even further behind in 5.4, especially with major buffs to most other classes.
The reasons why Shaman were used on cutting edge progression in 5.3 (and they were across the board benched in top kills of the 2nd most difficult boss - Dark Animus) are no longer really relevant.