I think the multiple Halos expanding and contracting could be good in some cases and not so much in others. I think that would benefit Holy more so than shadow.
But I do agree that it’s rather gimmicky.
If anything, would be cool if you could have less Halos… or a singular Halo as you have described where it is super pumped and juiced up to give that damage/healing you want alongside other buffs. Have that be a choice node instead of the lame Halo just does 30% more damage choice.
Then you can really pick if you want to have focused burst or spread consistent healing/damage.
Also, as far as visual aesthetics go, I ponder over the idea that Halo seems rather 2 dimensional and perhaps it need to be 3 dimensional in being an expanding Sphere instead of a ring. I mean a ring is more akin to a Halo but still… something about the description of Archon makes me think that you should be like an explosion of raw energy and explosions are not limited to 2 dimensions.
This once again makes me think of StarCrafts Archon as that is a being of pure radiant energy.
Maybe instead of Halo… you can pick Halo or Divine Star and the Archon Hero talent tree would convert either of those into Radiant Sphere where you explode energy from yourself when you enter your ultimate form (from your cooldown power up spells as you mentioned) and then you can cause more Radiant Sphere explosions of energy at your targets the next time you use X ability be it the Holy Word: Serenity or Shadow Word: Death as I have mentioned or other spells.
To me, that would much more capture the idea of becoming your ultimate self imo.
Edit:
Even further still, perhaps that radiant sphere could last for a bit and every enemy and ally within the sphere take damage and healing respectively as well as power you up so you deal more damage and healing while you are within the sphere. But the radius would have to be massive like at least the size of Mass Dispel targeting circle or even more.
I mean if we are going to remain immobile then at least we should gain some massive advantage while we stay in our sphere of awesomeness lol.
I’m kind of thinking of the Room ability that Law makes from the One Piece anime where he creates a giant sphere and can do amazing things within that sphere. Only we would do more damage and healing and perhaps other buffs like dealing more critical strike bonus healing and damage or something.
Or hey even better still, the sphere you create on yourself from your cooldown activation would just follow you (stuck to you) and when you create spheres around other targets, it follows them… not like how Entropic Rift “chases” a target but actually is a buff/debuff on the target that is stuck to them for the duration unless removed via dispelled.
Then if the target dies, the sphere would live out its remaining duration at the targets location so it doesn’t become a massive waste.
It’s like a super amped up Power Word: Shield except that it doesn’t absorb damage, it just deals damage and healing to enemies and Allie’s within its radius.
You should be able to deal more damage and healing to targets that are within the sphere and you will also be buffed to deal more damage and healing if you are also in the sphere so you can double dip if both you and the target is in the sphere.
Then Phantom Reach could extend the sphere range (radius) and you can have other talents that increase the potency of the sphere or the duration.
Here is a link to a previous thread showing off some interesting FX work and the sphere one could be a perfect fit for what I am envisioning.