As for Natural Spell: I'd be more inclined to just remove the feat, as allowing one to replace their physical stats with no drawback is clearly game-breaking.
That would be Wild Shape itself, not Natural spell. Natural spell just stops one class ability from interfering with another which is something that should never be allowed to happen anyway.
Important part in the original quote bolded. That's the point, really: Natural Spell makes the (rather large) opportunity cost of Wildshape go away, turning an awesome
option Druids get into an awesome
corollary of playing a Druid. Instead of a meaningful decision that impacts most of your actions further down the road (wildshape without NS), being in a powerful shape all the time just comes with the Druid's territory (wildshape with NS). That's the reason Natural Spell must go (and is banned in my games)!
But back on topic. Feats whose effects should already be in the game for everybody equally:
Weapon Finesse,
Power Attack,
Combat Expertise (stupid feat and ability score tax!),
all the Improved [combat maneuver] feats (why not let non-"I hit him again" tactics be viable without investing feats first?),
all metamagic feats (I'd remove the cost reducers, though... and no Invisible Spell in my game!),
Leadership (no cohorts though - just hire an NPC for good money, if you want one!),
Point Blank Shot (pure feat tax, no appreciable benefit, and logically, you shouldn't require training to hit better at point blank range...),
Precise Shot (What were they thinking? Another feat just to
not be hugely and arbitrarily penalized for your choice of fighting style?).
If these (and other, similar) things were automatic stuff you could just do if you were of that mind, everybody would be much more flexible, and much of the "feat tax" feeling would go away!