Hideous Laughter: This spell afflicts the subject with uncontrollable laughter. It collapses into gales of manic laughter, falling prone. The subject can take no actions while laughing, but is not considered helpless. After the spell ends, it can act normally. On the creature's next turn, it may attempt a new saving throw to end the effect. This is a full round action that does not provoke attacks of opportunity. If this save is successful, the effect ends. If not, the creature continues laughing for the entire duration.
This spell gives a +4 bonus against creatures not of the casters type and doesn't work on anything with intelligence less than 2, which means against anything but humanoids, it's pretty worthless. Furthermore, you get two saves and it does not allow you to coup de grace the target, nor does it allow sneak attack damage as you do not lose your Dex bonus to AC. You get a +2 to attack a prone target, but otherwise it just keeps the opponent from doing anything for a few rounds. You still must try to kill the oppenent the hard way.
Next, are the Save or Die series of spells, most of which were very powerful in 3.x. The Hold series of spells. (Which has the same silly wording. Take no actions at all, for the assumed duration, except on your next turn you can spend a full action to free yourself. Which is it??)
Save every single round. This time the opponent is helpless, and a coup de grace may kill it. This spell is absolutely worthless against anything that isn't a humanoid - such as giants, fae, dragons, oozes, monsters, animals, plants, constructs, undead, etc. This is a 2nd level spell at earliest casting, which means a 3rd level character can cast it. A CR 3 monster can be killed by a 3rd level fighter in one round on a good day or three rounds on a bad day without needing to concern oneself with saving throws - and it doesn't have to be human.
Flesh to Stone: Almost a direct port from the 3.x SRD, and... Still a fight ender, you save or you are effectively dead.
This spell targets fortitude, generally the strongest save for fully 3/4 of all monsters you will be fighting. It is also useless against any shapechanger, undead, or against anything not made out of flesh, such as elementals, constructs of the non-flesh golem variety, etc. Since it is a 6th level spell, the soonest it can be used is 11th level, which will be a later point.
Phantasmal Killer: Not only will it kill your target dead instantly, if your target actually saves, and has telepathy, he might turn it against you!
This spell is a 3rd level spell, and targets the two strongest saves of all - will and fortitude. Either save means the spell doesn't work. Instant death spell at 5th level with the possibility of the two best saves to negate? Not particularly overpowered.
Now, you state that all classes have the ability at 10th level to match these encounter ending abilities? Sadly, I don't see it. The fighter doesn't get anything other than 'Armor Training' and a paltry +1 with weapon groups that don't stack.
The +1 on weapon groups is an escalating bonus that nets the fighter a +4 with his main weapon group at 20th level. This seems paltry to you, but it is not. Why not? Feats. Lots of them. Explanation to come.
Bard? Nothing in Class, must be his spells. (No surprise there.)
Spells yes. Not a big deal, we knew this.]
Barbarian? Nope, nothing that instantly kills or otherwise removes the target from the fight.
And here we come to the crux of the matter, with fighters and barbarians and monks. The instant win spells you point out are useful, but they all have some glaring limitations as I described. If you looked through the feats you can see that they are not the same as they once were. Let us take a 11th level fighter, vrs. your 11th level wizard in comparison threat towards enemies of their CR rating.
At this level as an example, the fighter who has specialized in Power Attack, with Critical focus as well as Bleeding Critical and uses an elven court blade or falchion as his main weapon does damage of weapon damage average of 6+2+9+ 1 1/2 str + magic damage. At 11th level, this averages around a +6 bonus for strength (which goes up to 9 with the added two handed weapon bonus of +3) and +3 for magic (ignoring weapon enhancements other than simple magical for the moment). So, average damage of 29, multiplied times 2 for iterative attacks, which will hit two out of three times, so 58 damage on average per round. But every 4th hit is a critical, for which that average damage is doubled and will inflict 2d6 bleed damage for which there is no save. Note that this does NOT include Weapon Specialization and Greater Weapon Specialization.
Your average CR 11 monster with a full BAB will have around 160 hit points and good Fort saves, and most likely good Fort and Will saves. In three rounds, a fighter will have killed it inflicting average damage on 2 out of 3 attacks with no saving throws, no crits, and using a basic magic weapon. By himself. A single crit reduces that to two rounds. He'll survive, because his armor class will reduce the chances of his opponents hitting him by a great deal. He can reduce his damage output by an entire 4 points if he uses a ranged weapon from his second tier Weapon Training and Deadly Aim, which he will also be able to have via sheer volume of feats - this means he can cause an average of 25 points of damage at range each attack on average, meaning he's forced to spend 4 rounds killing his opponent instead of three without any help. To those who say, "but that's not an instant win!" I have one thing to say: If the opponent is dead, you win.
In the meantime, Hold Monster, Stone to Flesh, and Phantasmal Killer may also end the fight in a single round if the opponent fails saving throws. Three critical hits on the same monster by the fighter in one round will also end the fight in a single round. And Hideous Laughter doesn't kill anything, as there is no coup de grace or sneak attack damage available.
A barbarian is perfectly capable of emulating this to a large extent using rage abilities in place of weapon training, and will most likely be even harder for opponents to hit. A monk...well, considering he has the attacks of a fighter wielding two weapons, along with this stunning/exhausting/sickening fist abilities and potential trip attacks during these attacks to gain extra attacks as well as possibly using Ki to gain more attacks, all without spending a single character level feat to improve or gain these abilities, the damage values are not the same but pretty damn close. Rangers and paladins are just as effective against their specialized enemies as a fighter, and can certainly hold their own against their unspecialized enemies.
A lot of people respond to this argument by saying 'but damage was never the problem', to which my reply is 'damage solves the problem by ending the fight in the case of the instant win spells, and the revamped skill system and magical item creation ended the problem of nothing to do outside the fight'.
With the removal of the caster's abilities to emulate a rogue or fighter in any way and the remaking of monks into and bards into effective classes , no one class is obsolete, and thus there is no 'caster imbalance' issue that you are so intent on harping on in Pathfinder. With the changes in the skill system, a fighter will be able to be useful out of combat if he desires, and anyone can make Magic Arms and Armor if they desire. Pathfinder fixes 3.5 by opening up options that allow the player to build their desired character however they wish, including the ability to manage without true casters and still create a functional party - something impossible in 3.5.
This is just a restatement of something I've already pointed out in this thread done in great detail. And mind you, these details aren't even hyperspecific - this is an AVERAGE fighter, not a truly specialized fighter. A truly specialized fighter will be even more destructive. Feel free to check the math. The fighter's starting strength was 18, with his bonus points added to strength for 20, and a +4 strength enhancement bonus from a magic item.