As far as I understand it:
Nerfing Pargon Surge was about Nerfing Sorcerers and Oracles.
The ability to gain temporary spell knowledge, using a third level spell and a standard action, was thought too strong.
And yet, Wizards and Arcanists get arguably better:
Wizards and Arcanists can use Psychic Asylum (a level 6 spell),
to as a SWIFT action, memorize any spell in their spell book.
And
Arcanists (and Exploiter Wizards) can use a single point from their Arcane Reservoir,
as early as level 1, to change spells as a full round action.
This while Sorcerers are at every other level hugely worse than wizards...
At level 3 Sorcerers are say, Invisibility or Glitter Dust, worse than wizards.
level 5: they are Haste worse
level 7: they are Dimension Door worse
level 9: they are Teleport worse
level 11: contingency worse!
level 13: they are Limited Wish worse...
level 15: Polymorph any object...
level 17: they are Time Stop and Wish worse!
A similar argument holds for Oracles vs Clerics.
At those levels, they not only have access to a whole new ballpark of gamechanging effects,
they also have more total spells...
And on even levels, a sorcerer is still arguably behind, as they have no space, in their 1 spell known, for utility,
or long duration buffs like say, Mind Blank.
Not to mention Sorcerers having to spend more actions on metamagic, and having a hugely worse casting stat.
Why limit sorcerers using paragon surge to one single extra utility spell per day?!
Especially, when one of the few advantages that sorcerers do have, not needing a spellbook,
is in essence handwaved away, when the game assumes more or less unlimited access to magic items and scrolls.
The by far considered strongest sorcerer bloodline (arcane), is treasured for one thing:
making sorcerers more like wizards! While wizards get things like the Divination, and Conjuration (Teleportation) Schools.
It seems very strange that Paragon Surge was nerfed (rather than just limiting the Oracles' access to the wizard/sorcerer spell list). And talking about race parity seems a bit of a moot point, considering the Human Favored Class Bonus...
I think Paragon Surge was one of the few mitigating factors making playing a Sorcerer feel valuable, compared to playing a wizard.
I also think Paragon Surge is a really cool thematic effect, and that it is a real shame it is now so hobbled.