You can munchkin the hell out of the feat chain, that's for damn sure. You can get the same AC as magical plate and shield without worrying about plate and shield. So you could effectively be a monk in plate and shield or a greatsword weilding barbarian who retains 40ft movement and two hands and still has plate and shield, or wizard, etc. So it's definately broken in some respects. But if you're simply wanting to create a swashbuckling rogue with a rapier or longsword in one hand and nothing in the other and who wears a nice fancy silk shirt without armor then these feats can make you compete fairly well with an equivalent fighter in full plate with a longsword and shield. So if you keep the feats within genre they're good.
1st level 32pt buy Swachbuckler would be 10/16/14/14/10/14. IMHO a Swashbuckler would need high int and charisma for sure.
1st level 32pt buy fighter could get away with 18/12/14/10/10/10 and not break genre badly.
8th level Swashbuckler (ftr8) (+2 to dex due to stat raise, +2 more due to gloves, w/ +2 rapier, +1 amulet of nat armor, +1 ring of protection)
20 dex
Feats: Weapon focus, dodge, mobility, spring attack, weapon specialization, unarmored defense (intermediate+basic), weapon finese, ultimate finese.
+16 melee, 1d6+9 damage
AC25
+5 init (dex)
Compare it to an 8th level fighter with +2 full plate, +2 shield, +1 ring of prot, +1 amulet of nat armor, +2 longsword, and he put his raises into str instead of dex along with gaunts for 22str.
Feats: Weapon Focus, Weapon Specialization, Improved Initiative.
+17 melee, 1d8+10 damage
AC27
+5 Init (+1 dex, +4 feat)
And the platemail and shield fighter has 6 more feats he hasn't yet spent on anything like improved crit, etc.
10th level the Swashbuckler can get unarmored defense: advanced for an additional +4 AC over what he had at 8th. The fighter can get a +3 shield and +3 plate and they're still even at AC29. and roughly doing the same amount of damage.
My conclusion is that the feats aren't overpowered if you're making a certain type of character, but only a foolish DM would allow a wizard the type of protection afforded to a fighter at the cost of a measly 3 feats. It's best if kept to a certain archtype of a character.