The issue is that the pact is just a reason for why you have the power, but that really doesn't affect how the power functions. It doesn't actually answer what the power is, which is needed to determine what it should do.
I have said this many times. The pact imbues you with magical essence, turning you into a magical being = sorcerer; the pact lets you channel magic from a powerful being = cleric; the pact gives you access to magical knowledge = wizard.
Just because you have said it many times doesn't make you right.
Magical Knowledge makes you a wizard? What about Artificers, are they wizards? What about Bards, Lore Bards specifically seek magical knowledge, are they wizards? Druid rites are taught, are they wizards? Rune Knights are wizards, right, since they have magical knowledge of Runes?
Or well, Druids are clerics right? Except they don't need to have power from a powerful being. Nor do rangers, or paladins, but both CAN have that story. Or, what about a Barbarian, zealot barbarians are powered by their belief in gods, a god's blessing can be the source of their power, are they clerics now? What about Totem Barbarians? What about a Phantom Rogue whose powers come from a God of Death, cleric?
Ah, but the magical being part is totally just a sorcerer, right? I mean, if we ignore Genasi, Tieflings, Elves, ect ect then it is the only class that makes you innately magical.... except for Monks. And Paladins can be innately magical with their aura since they don't require a god, just an oath or contract with themselves, almost like a pact with themselves if you think about. And of course Beast Barbarians or Storm Herald Barbarians are innately magical as well.
Yes, Warlocks could get their power from access to magical knowledge from beyond mortal ken. They might get altered into a more magical being. They might draw power from an outside source. All of these are true... and all of them can be true AT THE SAME TIME. Just like a Cleric is pulling their power from a god, but can also be altered into a magical being by that god's power (forge cleric becoming resistant to fire) and can also have studied religious rituals to pull on ritual magic based on their learning. These are not solid lines that cannot be crossed. Everything is a bit messy, because the story can be a mix.
If both turn you into an inherently magical being then they should be represented by the same class.
No, because if that were true we would need to combine the warlock, monk, sorcerer, barbarian and paladin into one class.
Which event made you so is just backstory. Like we don't have a separate class for fighters who are knights and thus have sworn fealty to a liege lord. That is interesting, but it doesn't change their class whether their liege lord paid them to go to an expensive fighting school or whether they learned to fight on their own.
And yet we DO have a different class for the Fighter who swore fealty and the Paladin who swore fealty. What about a ranger who swears fealty to a Fey Lord and becomes a Fey Wanderer? What about a Dragonborn Phantom Rogue who swears fealty to an ancient Dracolich, becoming Dragonborn and gaining ghost powers?
It doesn't matter to me what the gestalt class is called. We can call it sorcerer instead of warlock if that's better. But the sorcerer fluff gets the warlock chassis, and warlock fluff gets assigned to this or some other class depending on what we interpret the pact to be actually doing.
Well, I disagree that the Warlock mechanics are the best way forward for the Sorcerer. I think they do quite well on the warlock. We need a different set of mechanics for the sorcerer, and I've already put my hat in the ring for something I think fits them far far better.