The problem with the class is that it has both heavy overlap thematically with warlock, while also having two different groups of players wanting 'their' interpretation of the sorcerer to be the one in game. And those interpretations are pretty mutually exclusive.
I think there is a lot of overlap thematically with cleric as well, and with more and more subclasses coming out, there will continue to be greater overlap.
Anyway, looking at the sources, I think part of the issue is Sorcerers having both a "bloodline" and "event" origin. Meanwhile, Warlock has their pact, but also "arcane research", which bends them a little towards the Learning/Study source as well, and the patron leans towards Entity.
SOURCE: DEAL ("Pact")
Warlock: Your
arcane research* and the magic bestowed on you by your patron have given you facility with spells.
*arcane research should be removed, or focused instead on the idea of "research of the entity" that becomes your patron maybe.
The focus of the Warlock shoud be the pact with the Patron. I've rarely seen this emphasized in play, and I hold myself guilty of that as well.
A question comes to mind and I think there are both views on this:
does the Patron bestow magic on a continuous basis so the Warlock must continue to abide by the pact, or once the pact is made and the Warlock gains the magic, is the Patron no longer needed?
In many ways, it seems to me that if the first (continuous basis), the Patron takes on as an Entity role, not necessarily "worshipped" however. Then, if the second case, the encounter with the Patron is an Event, and it becomes similar to the Sorcerer.
SOURCE: ENTITY
Cleric: As a conduit for divine power, you can cast cleric spells.
Paladin: You have learned to draw on divine magic through meditation and prayer to cast spells as a cleric does.
(Sorcerer: "Bloodline", the idea that your blood came from the entity, via a gift, pact, or whatever)
(Warlock: "Patron", the idea that your Patron is also an Entity, but does the power you wield come directly from the Patron?)
SOURCE: EVENT
Sorcerer: An event* in your past, or in the life of a parent or ancestor, left an indelible mark on you, infusing you with arcane magic.
I always found this interesting and sadly underdeveloped by WotC. The "event" is the key to the sorcerer. I would like to think if the event is an encounter with an entity, from whom you or your ancestor received magic, how does this differ from the Pact of the Warlock? I know it *can, the question is HOW???
Any other "event" works well IMO.
SOURCE: "Primal" FORCE (Nature)
Druid: Drawing on the
divine* essence of nature itself, you can cast spells to shape that essence to your will.
Ranger: You have learned to use the magical essence of nature to cast spells, much as a druid does.
*divine should be removed here. You already have the Nature Doman for clerics, so getting magic from a Nature diety should fall under that subclass and not Druid. Druid should come from the force of Nature, itself.
SOURCE: LEARNING/ STUDY
Artificer*: You've studied the workings of magic and how to cast spells, channeling the magic through objects.
Bard: You have learned to untangle and reshape the fabric of reality in harmony with your wishes and music.
Wizard: As a student of arcane magic, you have a spellbook containing spells that show the first glimmerings of your true power.
*ok, I really don't like the Artificer, but I think it would fall under this source.
That's it for the moment.