Enhancement needs tweaks more than a total rework. It needs some form of guaranteed rotational MSW generation that isn’t gated in the final talent tier. It could use some keybind decluttering such as removing Lava Burst from its spellbook and/or making Elemental Blast have no cooldown, and some clean up like changing Ice Strike’s effect to not be redundant with Hailstorm, and Windfury Totem being changed into a passive aura. It could use Primordial Wave getting a QOL redesign to be one button to directly blast all your Shock-debuffed targets for Elemental damage, instead of the PITA multi-step process just to cast Lightning Bolt once.
Most of all, it needs more ability to compromise between Elementalist’s “juggle these 10 balls that like to randomly rearrange their order,” and Storm’s “spam 1 until 2 lights up; repeat.” The tools are there in the tree to make a midpoint build with more interactivity than Storm, but less overwhelming than Elementalist, but the Physical/Elemental damage split forced on us in this expac by adding those damage amplification effects to Feral Spirits makes any build that straddles that line DOA.
Elemental I haven’t played since it was my off-spec in MOP, so I can’t comment there.
Resto, if any of our specs need a major rework, is probably the one. It’s straddling the line between being a reactive healer without the tools to react, and a predictive healer whose combos don’t live up to the number of binds that went into them, besides continuing to be saddled with a mastery that was designed for a healing paradigm that hasn’t existed since mid-Cataclysm.
My pitch would be to start by changing Resto’s mastery from Deep Healing to a new version of Cloudburst. Make Cloudburst its own separate spell that doesn’t overwrite HST. While Cloudburst is inactive, it collects a percentage of the shaman’s healing based on Mastery up to a limit determined by Intellect, then unleashes it all over, I dunno, ~8 seconds when activated, during which healing collection is paused. Stored healing decays over a short period while out of combat.
Cloudburst is a great idea held back by bad implementation (so, par for the course). The timing element of needing to set up a relatively long collection period that’s just wasted if it was dropped a second too early makes the spell frustrating to use, and frequently feel like it’s doing nothing for you. This change puts the timing fully in the player’s hands, which makes it much more flexible, and the rest of the spec’s kit can then be redesigned around it.
After all that, the class tree needs a serious pass, starting with redesigning it with nodes that change based on specialization. Specifically, Blizzard needs to accept the L on the idea that they can actually design spec-agnostic class trees for healer hybrids. Ele and Enh need off-healing utility in their class tree for personal survivability if nothing else, but any healing talents that are actually worth taking for dps specs are instantly mandatory picks for Resto. Meanwhile, we’ve got crap like Maelstrom Weapon and Flurry sitting in the class tree as nothing but trap picks for nooby Ele and Resto shaman who think they can actually make a melee hybrid build without being Enhancement.