This concept covers the clerics domains but ignores; Ocean/Water, Secrets, Lies/Trickery, Shadows/Darkness, Air/Sky, Fire, Wealth/Prosperity, Earth, Seasons (Winter, Summer, Fall, Spring), Destruction or Natural Disasters/Calamity, Fate/Time, The Hunt, Hope, Justice, Love/Lust, Luck, Strength(physical), Trade, Travel, Twilight/Eclipse, Dream, as well as more generally good and evil domains such as; Tyranny, Vengeance, Torment, Suffering/Strife, Pride, Joy, Justice, Humility, Hatred, Greed, Generosity, Freedom, Envy, Corruption, Community, Chaos, Balance, and Animals(Not Exactly Nature). Sure you could tag a few of these as aspects of these gods but you would almost need to make one good and one evil or have them just have evil aspects which while it would have less bloat than overlapping gods it is much more confusing to have two gods with 12 aspects each some of which are incredibly evil.
Not to mention you're ignoring monsters in their entirety, dragons are actual godly offspring, Tiamat is a god to the Chromatic Dragons while Bahamut is god to Metallic. Other monsters also have creator gods like the giants. Asmodeus and Vecna are two non-god beings that ascended to god-hood, I know if you craft your own world these characters can just not exist but you can't deny they're integral parts to understanding gods in DND, they don't all have to be good, Orcs and Goblins may worship different gods to Humans and Elves, if you want to erase their creator gods that's fine but it's kind of crazy to assume they follow the same two major deities. Even looking at the Yuan-Ti their whole business already revolves around a god of Multiple aspects heavily tied to snakes. And Kuo Toa literally believe their gods into existence.
If real life worked with DND logic where belief created the gods and gave them power, we would have the same level of bloat if not more, but gods themselves would likely be heavily tied to the regions where their believers are most concentrated. Think of it like a band, they're not gonna play a concert where they have no fans but that doesn't mean they don't play concerts. Gods not being as worshipped in the area as well as the presence of evil gods stacked on top of the limited amount of intervention gods are allowed to do cause for only the most religiously devout to be heard. If you had 1 cleric in the party their god is being channeled through them, If you through a party of 5 clerics/paladins with 5 different gods then you will likely have 5 gods intervene. It's the players themselves that channel the gods power so the lack of a follower to act as a conduit is more than enough of an excuse for lack of a gods intervention. Additionally I want to add, If a character plays a fighter but roleplays religious activities such as praying every night before bed, leaving symbols of their god around, and openly fighting in their gods name, when Big Bad Wizard is gonna destroy the world you best believe that fighters god should help(assuming the DM is competent and any cleric or paladin doesn't feel as if their toes are stepped on), or likewise a Warlock if fervent in their veneration of their Patron should absolutely get help the same as a cleric.
Also your idea lacks the concept that everyone always believes their god built them in their image. Elves will believe their gods are elven, Humans likewise, and Orcs will be no different. In dnd Lore if there was 1 god that created all the races that god would likely be split apart into several lesser versions to fit the ideals and visual preference of each race. And you seem to have ignored the part that is what allows evil gods to exist in the first place, Worshippers isn't the only way God's can maintain their power, The level or Worship itself effects the gods power. Ritual sacrifice and great deeds made in a gods name help bolster their power far more than just ordinary worship, so gods, particularly evil ones, with very few followers relative to other gods can still be as powerful as them.
I think your idea would work as the two gods you made are the greater deities of the world, perhaps you can give an additional aspect to each one, the sun getting positive domains and the moon getting more evil domains for lesser sects or cults worshipping them. Then you can add the intermediate deities which can hold maybe as much power as a single aspect of the greater deities but having significantly more of them and maybe making some creation lore specific gods like Tiamate and the all father, more involved gods. Gods that are core aspects of a race like Lilith, Maglubiyet, Asmodeus, Bahamut, Gruumsh, Corellon, Etc... could all be kept as race specific gods as their creators (you can make your own but I just listed names), perhaps even allowing them to hold 1 or 2 of the same domains out of 3 or 4 total Domains each. And then have the Lesser Deities that only hold 1 domain each and fill out the rest of the unfulfilled Domains.
Even that system just doesn't work well since God's having races makes so much more sense. Having this much bloat makes sense, so many different cultures and creator gods within the lore it only makes sense that the different cultures developed different religions. If you took just a handful of Real world cultures you could get more gods than what is in dnd, Just take Christianity, Norse, Greek(Or Roman), and Shinto. Christianity would give you a "True God" like Ao and sort of Asmodeus as Satan as just a main two. Then Greek has 12 Main gods that could be greater deities, as well as others which reach a total of at least 58 many of which hold the same domains at the same times. Then adding in norse with another 66 total, 13 of which are agreed to be the major ones. and lastly Shinto which throws in (from what google tells me) an extra 8 Million, 65 of which are considered the Main Gods ignoring the extra Kami. Ignoring the Kami that gives a total of 191 Gods between four different cultures. In dnd I could find over 50 fully unique PLAYABLE races ignoring halves or things like the different elements of genasi or variants of elves. Each one has thousands of years of history from the dawn of time likely having crafted their own religious beliefs, following an average we could see well over 2000 unique gods belonging to 50 pantheons basing it off real humans. This is also ignoring monsters like Dragons, Giants, and other monstrous races that are intelligent but not playable in official dnd material. It would make sense over time for a lot of these gods to meld into one another through thousands of years or for holes in some cultures be filled by others until the bloat is greatly reduced as gods would likely fight for dominion over their domains in a world they can interact with this would be double effective. I'd like to see an early dnd world where the DND equivalent of Zues Vs Odin takes place in which all mortals can spectate so in the end of the battle winner takes all until a more Ordinary Pantheon Size is reached. In total I counted a little over 150 Dnd Gods (In the forgotten Realms) but keep in mind almost every major race, monster or humanoid, all had their own Mini Pantheons with a handful of gods. Keep in mind most of these gods are likely Lesser or Intermediate meaning they have less strength over their domains and are less capable of interacting with the material plane, and many gods are largely evil and wouldn't help the players. Many are also neutral or wouldn't want to interfere with the material plane for their own reasons. Majority of Gods wouldn't care if some super powerful Evil Lich was attempting to take over the world, why would the god of Oozes (who is also a Demon Lord in the abyss) care about the material plane? Why would the main god of Goblins Care if they're enslaved by the Evil Lich(if they die sooner they get to serve him in the after life sooner)? Asmodeus would likely be happen as more death and oppression means it's easier to get souls into the hells to fight the blood war and it's easier to offer deals to Mortals who are in worse situations. Evil gods like Bane would be delighted in a world so full of strife. Mystra has no reason to stop a powerful Lich, as they're likely studying to further Magic and thus an asset to her more than 100,000 commoners killed by the lich could be.
It isn't just plot convenience to not have most gods help, even to have one help is a world defining moment worthy of the heroes. I understand the complaining about the bloat within dnd gods but it makes sense to have 10x the amount of gods seeing as there is so many cultures in the world, humans alone with no tangible intervention created thousands of gods before our total population reached 1 billion. I'm pretty sure there was a large chunk of time in DND lore where gods literally walked on earth until they were eventually banned from the material plane, in which mortals literally helped kill gods. I could keep yapping on and on about how much sense it makes but I've already written a book nobody will read so I will conclude my Yapping session.
