The breakdown of subclasses into "ancestry" or "environment" is an intriguing way to go...but ultimately, kinda "same-ish." I mean, the just about ANY Sorcerer Origin could be from an ancestor or their environment. A "draconic" sorcerer could be because great grandpa was a dragon...or because great grandpa lived near or served or was favored/granted powers by a dragon. A "storm sorcerer" could be -as the SCAG states- because you were "born during a particularly terrible [and obviously magical] weather" (which I find to be utterly ludicrous) or, maybe, great grandma had sex with a djinni or other air elemental or a weather-related fae/sidhe, demi-god, storm giant, whatever...You can be a "fae sorcerer" because your father is a faerie prince or you were birthed in a stone circle on purpose or accidentally in a "faerie ring" of toadstools.
My point is, that/those origins are just all story. It's not really a hook to hang your subclass feature/mechanical divisions on.
I think the more evocative, and arguably allowing for more creative backstories, subclass "Origin" breakdown would have been (or "would be" if you're "Building a Better Sorcerer") to divide them up by the focus of their magical powers.
To whit...Elemental Sorcerer: You choose one of the following elements around which your magical spells and subclass features all use/rely: fire, cold/ice, earth/stone, water, air, wood/plants, metal/magnetism.
Enchantment Sorcerer: Enchantments, Illusions, emotions, dreams, charming things.
Mind Sorcerer: telepathy, clairvoyance/precognition, dreams, astral travel, "person" and "animal" control.
Force Sorcerer: basically ramped up telekinetics, forcefields, shooting force bolts, lifting, "holding," carrying/levitating (self and others).
Base features, essentially, stay the same: Spell Points & Metamagic tricks. Subclass features get broken down, roughly and with different subclasses possessing different strengths in various areas (obviously), into things you can spend spell points on to do things with those powers in a "macro" sense and/or alter/adjust spells that work with your area: every subclass would get some kind of offensive attack, defensive use, non-damaging offense, detection/divination/information gathering in your area of expertise, movement use, bonus to/adjust your saves for something or the other, etc...
Is your background some extraplanar ancestor? Powerful material plane creature? Magical experiment/mishap? Vortex of Power location? Supernatural/Preternatural disaster/occurrence? Someone cast a Wish somewhere (either directly on you or in your family's past or that had nothing to do with you but was poorly worded and went awry)? or you have no idea/"I was just born this way?"
Doesn't really matter, does it? Any of those could work for any of those options...a hundred different ways.
You want a better Sorcerer? Revamp how the class is structured/divided. Remove "Origins" and insert subclass "Power Foci."