Taven and Daegon feel like some kind of JRPG plot, as Trash mentions. The whole backstory with their parents doesn't make any goddamn sense,
It makes perfect sense to me.
One of the Elder Gods was corrupted (Shinnok) so their power of seeing the future was obscured. But Delia, a powerful sorceress, had a vision of the battle of Armageddon where too many powerful combatants would participate and where a surge of power would bring upon the destruction of all the realms.(which ultimately came true, but that's another thing).
Because Argus and Delia were loyal to the Elder Gods, they asked them for a solution. No army in the universe was powerful enough to stop the 64 combatants, so Blaze was empowered with so much force from the Elder Gods themselves that a hero could harness it and kill/render powerless the others. Because no mere mortal could harness that power, the Elder Gods had to trust Taven or Daegon. But were they worthy? They put them in stasis until they could prove themselves.
Shinnok, being the corrupted Elder God that he was (which the others couldn't sense), stepped in and somehow awakened Daegon very early, lied to him that his parents preferred Taven and made him kill Argus and Delia. Shinnok probably also found Blaze and secured his corruption by the holy men of Onaga, to disrupt the plan of the Elder Gods and make the power available to everyone when the time came. In Daegon's MK Armageddon ending it is said though that his awakening was allowed by the Elder Gods and Argus to test his heart.
none of it fits Edenia as previously established,
Here I kind of agree. In the MK Armageddon intro scene Argus and Delia discuss their plan looking from the balcony as they make it clear they're engaged in War with Outworld and Shao Kahn. Even more so, Taven discusses during konquest mode how he and his brother have fought against Shao Kahn once and pushed him back from Edenia. This means that the action was AFTER Edenia had lost the 10th tournament and Shao Kahn was able to invade, around 10.000 years ago. No way had Shao Kahn tried to conquer Edenia for millions of years....come on! But even if the events had rapidly succeeded: Edenia loses 10th tournament, Shao Kahn's forces invade, Argus formes the Edenian Resistence, Taven and Daegon aid King Jerrod and fight off the invaders with an Edenian-Seido alliance (mentioned in the lore), one of the Elder Gods is corrupted and they can't see the future anymore, Delia has her vision, the brothers are put into stasis, Daegon is awakened, kills his parents, Edenia is doomed, Shao Kahn enters and kills King Jerrod, names himself rightful Emperor and declares a new religion where he is worshiped, the Elder Gods are weakened so Shinnok attacks Earthrealm, the planet is ravaged and almost destroyed (the mythological flood from almost all religions which historians place around 8.000 BC= 10.000 years ago), but a few humans and saurians are protected by Raiden and Fujin who manage to take the Amulet and lock up Shinnok in the Netherrealm, saurians are given a new home in Zaterra, humans start over, probably with Edenian refugees coming to Earthrealm around 10.000 years ago bringing with them the Agricultural Revolution (correct from a historical standpoint)................even with these events rapidly succeeding, it still leaves the question as to why Shinnok would say in MK4 "For millions of years I have suffered in the Netherrealm". Either NRS didn't think the story through and it's just a mistake, either Shinnok is exaggerating his 10.000 years in the Netherrealm (which makes sense since it would seem that way when you're trapped in Hell). Because the only other way it would make sence is if Shao Kahn had attacked Edenia for millions of years, which in my opinion is lame (considering that MK1 to MK 3 action takes place in a month or so).
the talking dragons are so goofy,
I think they're a symbol of origin, loyalty and wisdom. I think they are really really cool, but every man is entitled to his opinion.
Taven's and Daegon's designs are generic as balls, and the Red Dragon didn't do anything but confuse the issue when the Black Dragon was perfectly fine thanks.
"Oh, the Black Dragon is just an offshoot of this cooler older thing." No, that's dumb. A clumsy retcon -- plus, way to undercut Kano and Sonya, two of your original characters, by making their cool rivalry a minor part of some cosmic whatever.
Again, it's a matter of opinion.