I guess I'll just throw my feedback on the pile. In the quote, I've bolded the parts that I like. Criticisms first, followed by positive stuff:
Aero 3/Refulgence is okay, but it's not worth an extra button slot. It's just 1 button you press once after mobs are grouped up. People already use Dia on the first pack while running to the next one, and this would overwrite that for almost no gain. You'd just be replacing Dia spam with one Refulgence, and then you have nothing to cast while running. Besides, WHM already has plenty of AoE buttons (especially if Bloom is AoE).
Thundercloud only works on BLM because it's used for movement, filler during Ice phase, or DPS. Balancing those 3 applications makes it interesting. Thundercloud on Dia would change nothing: you would still try to reapply the DoT every 30 seconds.
Afflatus Inspiratione is debatable, but at the very least it needs to be weaker than that. At 300 potency, it's nearly the value of a Succor shield, almost for free (just 1 lily charge, and we have a plenty of lily charges nowadays). For Ultimate and early Savage prog, mitigation is very important, and this could provide an extra mitigation on every single big raidwide. I already think Collective Unconscious on AST is maybe too much mitigation for a pure healer, and this is better than that. Maybe it would be balanced at 200 potency, but it's still feels like an out-of-place ability to throw on WHM. It adds shielding output, but doesn't add interactivity in the kit. (Although it would make WHM/AST a more viable team, to match SCH/SGE. Not sure if that's good or bad.)
On to the positives. Misery is definitely crucial to end-game WHM gameplay, because it shifts a huge amount of power (and fun) into the lily system. As a side-effect, this also make WHM much more flexible because lilies can be used for movement. Making a version of that available at level 52 would help a lot. Being a little conservative though, I would say it's not needed until level 62+. WHM gets a lot in HW, and almost nothing in StB.
The GCD Combo into Bloom I think is pretty much what I would expect SQEX to add to healers. Because it adds a little depth/busywork for the veterans, but ultimately is not very impactful (i.e. casuals can ignore it and not lose much). Maybe that sounds like a complaint, but I think it's good because it gives veterans something extra to track, and you can get very precise about it, but it doesn't hurt much if you drift cooldowns or screw up the combo. (While using Shine/Smite, you want to pay extra attention to the Bloom cooldown, in case the reduction makes it come off cooldown early.) I'd just make Smite reduce the cooldown by 2 seconds to differentiate it from Shine.
The 10% blood lily buff isn't super necessary, but if it's a short buff (like 5 sec), it could be interesting trying to align it with Misery and burst windows. Mixed feelings on that though. It might be one-too-many things to optimize at once, and thus might be frustrating when things can't be aligned properly. I would want to test it before concluding anything.
Oh and I almost forgot. I've advocated for 2 charges on Assize in the past. It's an easy win-win-win. It can be used back-to-back for big burst, so it's fun. It would be available for healing more often (even when trying to use both charges in raid buff windows), so it improves the versatility of WHM. And it's easier to avoid drifting the cooldown, so it lowers the skill floor.
Overall good post, OP. Some of your ideas are crazy, but I like the initiative.