I proffer this answer only because @Zach doesn't like the answer provided above which, from a system point of view at least, is more consistent and easier to implement for the GM. However, here are some other options to work around the inherent imbalance of monster races without @Gates answer:
First and foremost - try to consider balance to be more than the sum total of what the system has to offer (and especially the combat system). In the example of the ogre you could:
- Make it apparent that life is difficult for creatures that big when pretty much everything is made for smaller folks: "Er... yeah - I repair weapons but something that big? I don't even know where to start. Leave it with me for a couple of weeks and I'll give it a go but don't expect anything quick or cheap"
- Play up reactions to the racial stereotype. There's likely to be settlements that just aren't comfortable letting an ogre wander around them.
- Magical items - in a campaign where they're relatively common how many are they going to find that actually fit an ogre?
- Transport: horses, coaches, boats etc are all likely to be difficult propositions.
- This one takes a little more work - but you can provide a slightly different perspective on the world with some effort to re-describe things for a less advanced race who might not understand the technical or social nuances of other species.
All of the above take more effort than just throwing in some checks and balances at character generation but they can add a lot of atmosphere to the game. I would also strongly advise talking with your group about whether any of them would help provide the sort balance that you want - after all there's not point putting balance mechanisms in that either don't work for your group or make the race entirely unplayable for your players.
Here are a few things to consider :
Tactics
If a full attack is "all" it takes to down someone, force Move actions. Could come from cover/concealment or combat maneuvers like Trip/Knockdown or Disarm. If you just play "rocket tag", you're implicitly accepting that if you miss, there's a good chance you're dead.
Note that this is exactly what happens IRL between powerful forces in a battle and in this respect, is not a "bug" of the system but a simple truth.
Intelligence
So you're targeted by a Master Ninja, who manages to sneak up on you and place a Death attack. Curse you, Hayabusa ! Wait, you made your save ! Time to grab your trusty bow and fill him with arrows...
Well, boo. The ninja has broken/stolen your bow as well. Not only does he make his escape, he's slowed you down by forcing you to have it repaired / replaced while you try to get it back.
This goes a step further in Tactics, and is to be expected of Ninja, for example. Study your target. Know their strengths and weaknesses as well as yours. "That Brilliant Bow of Badassitude could be a problem if I must escape. Can I get rid of it ? What about impairing the bowman ? Maybe I could blind him ?"
As an aside, the GM should make sure the players don't feel cheated though. Extreme competence is assumed as part of the characters (especially past level 10) and robbing them of that can be frustrating to no end for some.
Numbers
So they can take the Big-Ass-Monster down in a round ? What about 10 Medium-Sized-Nuisances ? One by itself could barely hope to hit them, but with flanking, teamwork feats and simply being all over the place, the little pests could prove to be annoying. Add in a Leader-type and you could even be worrying your characters.
Story happens
Take the characters down a notch or two through Story. Have them stripped of Rank and Privileges by the King or even make them straight Outlaws. Have them stranded on an island (and some of their equipment lost to the sea) after their boat got caught in a storm. Have their home base attacked (and their Mentor killed, leaving them unable to progress in their main class) while they were on mission.
Change focus for a while
Once all is said and done, if the combat has become so easy it's boring, it may be time to try a little courtly intrigue for a change. Or why not a mystery ? Possibly meshing with "Story happens" above, there are plenty of opportunities to take the players / characters out of their comfort zone while staying true to the setting. They'll be happy to resume bashing heads once they've stumbled for hours finding a tangible threat to pounce on. Or hey, maybe they'll actually enjoy trading piques with the Jester and decide they want a piece of land and a throne of their own ?
Best Answer
Pathfinder essentially exists as a backlash to 4th edition Dungeons and Dragons - it is derived directly from the third edition ruleset, intended to try and fix some of its biggest issues without significantly changing the underlying ruleset - in comparison to 4th edition, which was a drastic change to the system that proved highly unpopular with a large subset of D&D fans. It's also published by a different company, Paizo, taking advantage of the very permissive OGL license that 3/3.5e D&D were published under (another thing which 4e dropped, which people were also unhappy about).
The target audience was essentially people who already liked 3.5e D&D, wanted more 3.5e D&D, and probably already owned a lot of 3.5e products. It was therefore in Paizo's interest to make it a selling point that existing 3.5e material was broadly compatible with their new rules, so that customers would feel able to take advantage of their existing 3.5e content (and the time and money they had invested in that) and would not feel that they were essentially throwing it away by transitioning to a new system.
The "compatibility" is basically that with a little bit of effort you can translate 3.5e content into Pathfinder's rules relatively easily - Paizo produced guides on how to copy 3.5e characters into Pathfinder. As a direct derivative of 3.5e rules, Pathfinder is even sometimes referred to as "3.PF" or "3.75" D&D.
The same cannot be said for Pathfinder and 5e D&D, as that did not exist when Pathfinder was created (and so could not be designed for). Though 5e is certainly closer to the 3e/3.5e ruleset than 4e is, it's still significantly different to the degree that translating material is not the relatively simple job it is for 3.5e->Pathfinder conversion. Wizards of the Coast don't have a great deal of interest in keeping mechanical compatibility with older versions of their own game, let alone the derivative version of their old game published by a third party.