Skimming through, it looks like you took a bunch of feats & PrC class features, and made them into Sorcerer class features.
So you're basically saying: "You won't want to PrC out of Sorcerer ... because I put a bunch of PrC into Sorcerer!"
It's possible to make that method technically sound from a balance perspective, but IMHO it's pretty unsatisfactory, because making every Sorcerer into a hybrid Sorcerer + Archmage means that there's fewer interesting combinations across campaigns... and I haven't actually seen if your method is actually technically sound.
Some of these ideas seem like attempts to emulate Wizard flexibility, but without the associated costs. For example, being able to swap out one known spell for another is more like Cleric flexibility -- since you don't need to locate the replacement spell, nor pay to scribe it, etc. -- which takes out an element of... maybe balance, maybe just a reward for thinking ahead.
Other ideas seem like they're pointed at specific CharOp arguments against Sorcerer (e.g. "Use Cha for Spellcraft" => Incantatrix justification). I'm not sure why Knowledge skills got dragged along, though.
All in all: I mostly see a bump in numbers, and some huge flexibility increases which might be broken, but no distinct niche or playstyle enabled (other than intruding into the Wizard's shticks).
== == ==
Here's what I did for Sorcerers in my games:
- All Wizards must be Specialists.
- Wizards don't get bonus [Metamagic] feats. They must use their bonus feats for [Item Creation], Spell Focus, and stuff that has their school specialization as a prereq.
- Sorcerers get 0 + bonus spell slots (but no spells known) at every odd level. This keeps them competitive with Wizards for entering PrCs.
- Sorcerers get Eschew Materials at 1st level, and a bonus [Metamagic] feat every 5 levels.
- Sorcerers can use [Metamagic] feats on spells without increasing the casting time.
- Sorcerers get 4+Int skill points, and a better skill list.
If I were going to do my campaign houserules over, I'd probably do a bit more for the Sorcerer, but that little bit above was sufficient to make them as playable as Wizards in my jungle -> urban -> planes -> martian dungeons -> more cities -> more planes campaign.