Some suggestions will be minor, some major, others experimental, etc. Here goes.
(1) Scrap tier 15. It’s boring and the only thing worth salvaging is the Execution Sentence animation.
(2) Tier 30 is another filler tier. Scrap it and bake Blade of Wrath into the baseline BoJ proc. Hammer of Wrath should be on a more impactful tier where it can do more damage, or generate more holy power, or something. It’s so neutered right now.
(3) Tier 45 is pretty good. Only suggestion I would make is Fist of Justice reduces HoJ’s cooldown by a flat 30 sec. Maybe also make Repentance instant with a revised cooldown and duration (for Ret only obviously).
(4) Tier 60: replace Divine Judgment (dead talent) with Empyrean Power, which should have a spell alert. Give Consecration a secondary effect to make it more appealing. Make Wake of Ashes baseline and have it stun aberrations in addition to demons and undead (flavor). Create a new talent to round out the tier.
(5) Tier 75: replace Eye for an Eye with Divine Protection (more versatile) or, better yet, Ardent Defender. Cavalier should reduce the cooldown of Divine Steed by 5 sec in addition to its current effect (minor buff).
(6) Tier 90: JV has been a dead talent all expansion. It even loses to Selfless Healer as a leveling talent. Reduced holy power cost? Free after a killing blow? Heals you even if the damage is absorbed? Or, replace it with something new. Next we have Word of Glory which is mandatory for mythic+ and useless in PvP (40% reduction). I don’t like talents like this, although I admit it is fun in mythic+.
(7) I think tier 100 is very well designed. Divine Purpose shouldn’t deal such reduced damage in PvP though. No one takes it anymore.
(8) PvP talents: I haven’t used Cleansing Light, Divine Punisher, or Luminescence once this expansion. Jurisdiction isn’t terrible, but would benefit from being combined with another talent. Vengeance Aura should be an aura: remove the greater blessings limitation.
(9) Unbound Freedom is awesome and Ret has been so much more fun ever since it was added. This goes to show how far a single change can take a class.
(10) Moving onto baseline changes. Crusader Strike, our filler attack, doesn’t need two charges. Give this to Blade of Justice (it will feel great with the proc. I’m surprised this hasn’t happened already).
(11) Crusader Strike is basically an auto-attack that generates holy power and it always feels bad when you reach that point in the rotation where you have to use it. Suggestions?
(12) Greater blessings are boring. Make them raid buffs: Might is Battle Shout and Kings is Fort. Or, get rid of Might and have Kings be a unique buff that increases all stats by X%. Raid buffs are fun because they’re impactful, it’s fun to watch your raid light up, and you can cast them on people passing by out in the world. Holy and Prot can get these greater blessings as well in the interest of making classes feel more cohesive again.
(13) Give Ret back Blessing of Sacrifice. At character select back in the days of yore I chose paladin, not Retribution.
(14) Delete Rebuke from the class. A few other specs in the game could stand to lose their interrupt as well. Prot will be fine without it with their Avenger’s Shield spam.
(15) Replace Cleanse Toxins with Cleanse (dispels magic). Druids and shamans should not have magic dispel.
(16) Replace Blessing of Sanctuary with a PvP talent that reduces Blessing of Protection’s cooldown to 30 sec, but removes its entire duration. It’s a physical debuff dispel, and yes, it can still be cast on yourself while under the effect of a physical CC.
(17) I’m not sure if this is possible since Holy Light is a very different spell than it used to be, but I miss having this big, inexpensive heal I could cast if no one was attacking me. Ret only having Flash of Light, and therefore no choice in what to cast, feels very one-dimensional. I think the word I’m looking for is “pruned.”
(18) Bring back Turn Evil. Replaced by Repentance or Blinding Light if you choose to talent into one of these. Blinding Light lasts 12 sec against demons, undead, and aberrations.
(19) Exorcism must return as well, but I’m not sure how to go about it. Obviously it should deal increased damage to demons, undead, and aberrations (and we’re not balanced around this - it’s just free damage and paladins do a little better in certain situations. WoW is an RPG, deal with it).
(20) Bring back Divine Intervention. It was hilarious and occasionally useful.
(21) Add a minor glyph that replaces Divine Steed’s graphic with that of Speed of Light (from MoP and WoD). Not everyone likes the horse and SoL is a cool graphic in its own right.
(22) I should probably get ahead of this before someone brings it up: seals and auras. I really enjoyed Empowered Seals in WoD, but that wasn’t for everyone and there have been more bad seal system designs than good ones. As for auras, they’re cool in theory but boring in practice. I’d rather our utility come from more active sources. How about we just give paladins baseline Crusader Aura so our friends can keep up with us.