The Wizard, Cleric, Druid, and Warlock are only casters with special proper mechanics.That implies that the other full casters all have "proper mechanics" and the Sorcerer doesn't... which I don't think is really true either. The Bard, Cleric, Druid, and Wizard all have standard full caster mechanics but none of them are all the special over that moreso than the Sorcerer. Bardic Inspiration, Channel Divinity, Wildshape, and Arcane Recovery are not any more impressive or proper than Metamagic.
All five classes are standard full caster classes, none of which have mechanics that are so wildly different as to make them special or "proper". So I don't see why Sorcerer requires something different over what they already have. Heck, the Sorcerer's Sorcery Points and Metamagic are arguably even more a "proper" mechanic than whatever the Wizard has currently. The only real "special" mechanic the Wizard gets is a larger spell list.
The Warlock and Druid ones from 2014 don't work and got heavily play tested in 2023 because of it.