Mesh I know people don't seem to like referring to Everquest, but I'm going to do that because M&M Shaman was ripped directly out of the Everquest book, and then they crumpled that page up in their fist to bring the class to its current iteration we're playing now.
In both Everquest and in Monsters & Memories, the Shaman class was designed to have more mana regen than the other healers. 54 MP6 is a lot. In Vanilla Everquest, Cannibalize IV gives 162 MP6 more than the other healers. Vanilla Everquest Shaman are not considered the best healers despite this. The balance is done in other ways, providing unique identity to the different healing classes. Having more mana regen is not the class identity.
Shaman in Everquest was largely balanced around having to spam the Cannibalize button, while a ton of other button clicks fought for priority - they couldn't cast everything at once. As you introduce longer cooldowns to Canni, the only levers to balance are the health:mana ratio / the amounts, and the cooldown. Or reinventing the wheel, which they are attempting with Consuming Pact. I think this button feels both too good and too punishing. The ratio is too high, but so is the downside. The healing debuff is too harsh and severely punishes every point of damage you take from a mob, in a way that does not feel fun or engaging. It feels like you are cowering in the back of the group even more so than a cloth caster.
The other way Shaman was balanced in Vanilla EQ is the same as they've done here - by making their HoT (Torpor) extremely good but having their single target direct heals fall sharply behind the other healers. Our max rank direct heal does 638 healing baseline. Compare this to Cleric's max heal with Renewal IV at 1191 healing baseline and with a better ratio (~ 40% better ratio - a pretty big deal). Druid is similar and has additional self-synergy. Especially after the HPS nerfs, Shaman HoT will not be sufficient to maintain a group - we'll have to use our single target heals substantially more, and they are quite substantially worse. As harder content comes out, this issue will be exacerbated.
The Shaman class from 2-3 months ago was designed from the bottoms up to be incredibly similar to a lvl 60 Torpor Shaman in Velious - clearly the direct inspiration. I believe that designer is no longer here, and the person taking it over scrapped trying to balance that vision. I think that is very unfortunate and that diverging from this vision was a mistake.
If Enchanter doesn't lose haste or slow, then Shaman in this game will be in a bad state. Relying on another class being stripped of their historical spells is not the right way to approach balancing the Shaman class.
There are a lot of people in this thread saying Shaman is in a fine state, and almost none of them are Shaman mains. This is pretty telling.