I Loathe Pathfinder

It's true.  I despise it.  I find it bereft of any value as a game system and find the art regrettable.  I have many reasons for this, such as that it has too many options that don't substantially alter the game's core classes and it's spurious improvements to the 3.5 system are merely poorly designed constructs adding to the weight of an already bloated and poorly designed system.  It reminds me of programming where fixes are done by adding more lines of code rather than removing bad code because the program is so poorly designed that any removal would break the whole and nobody wants to take the time to do it right.

shower of bastards

One of the most egregious sins of 3.5 and thus Pathfinder, however, is the open nature of the math.  Prior to 3rd edition the D&D game was a closed system, mathematically speaking.  No ability could be above 25, and indeed the rules explicitly forbade characters from having stats above 18 without major magical enhancement, like several wish spells or the actions of an extra-planer entity.  Ogres had 19 strength, which made Gauntlets of Ogre Strength pretty damn self-explanatory and useful.  Fighters loved to get a pair because it dramatically increased their mathematical advantages in combat and outside of it when it came time to lift things or bend them.  When you know that 25 is the strongest anything can get and you know that you will never get there it makes things like Titans quite impressive.
In those days the rule of 1 and 20 was also in effect for EVERYTHING, combat, proficiency checks, saving throws, you name it.  Because of this rule the best chance you could ever possibly have in any action was 95% (every pip of a d20 is a 5% chance of success/failure).  Also this meant that the worst your chance of success could ever be was 5%.  You had a hope of success in even the most dire situations.  Every +1 bonus was a 5% chance increase subject to the 95% cap of the d20, and the same was true in reverse with the penalties.  With an AC range that was quasi-capped at -10 to 10 you also knew that things were never going to be absolutely out of control.  I say quasi-capped because occasionally you'd see a -11 on some truly nasty beast just to keep you in your place.  Those were rare and special moments.

The 3.X/Pathfinder method is open-ended, however.  Magically enhance some raging barbarian and see a massive Strength value of 26, 28, maybe in the 30s...it doesn't have to stop as long as the bonuses stack.  The practical result is that you can have monsters with Strength scores of 60, 90, 145 if you like in direct contravention of the square-cube law!   Let me put that into perspective.  A Purple Worm is a Gargantuan size beast meaning it is between 32 and 64 feet long weighing 16 to 125 tons.  It has a Strength score of 35 (that's +12 to hit and damage) which means it can shift a lot of weight.  Only it should really be more vulnerable and weak, comparatively, to a human due to its volume versus its surface area and its bulk.  Effectively it takes more strength to keep this monster, which is terrestrial, moving giving it less strength to apply to things like combat.  Oh, it is absolutely stronger than a human, but comparatively not so much.  The ability scores are absolutes, however.
WAIT, ASSHOLE, THIS IS A FANTASY GAME NOT A SCIENCE LESSON!

Aaahhhh, toothy asshole attack!

I know, so I'm going to stop with the physics and get back to the main point about an open system, which is that the open system becomes all about stacking the bonuses.  While the d20 is still subject to the 1 and 20 rule and the +1 is 5% still, the action of it changes.  When you have a reasonable -10 to 10 range of AC you find capped 25 ability scores to be fine.  However if AC has no upper level limit (and it does not in 3.X/Pathfinder) then you must keep looking for those bonuses and asking yourself, "Just how does that guy get such a high AC?".  But the rule of 1 and 20 is still in effect so now there you are with an AC of 48, meaning that an attacker of BAB +2 must roll 46 or better on a d20 to hit and he rolls a 20 which always succeeds and you've just been hit.  Why did you spend all that effort getting such a high AC?  Was 46 not good enough?
Well if your foe was a 20th level Fighter his BAB would be +20 and his strength bonuses by that time would probably give him a +5 to hit (+25) not counting magical bonuses for weapons and such.  See, now all he needs to roll is 24 and we haven't done magic weapons.  This leads to problems where a +1 magical sword, previously nice to have, is not some sort of booby prize.  Nothing less than +4 to begin (+20%) and you won't really be happy until you have a +6 sword of flaming burst that does +8 to undead and purple worms.
It becomes a mathematical arms race.  The monsters need MORE HIT POINTS to be a threat and so the players need more HIT POINTS and bonuses to keep up.  Except wizards, of course, who still keep taking it in the ass with the d4 Hit Die.  No wonder so many of them become liches...they need the Hit Points.

It's not just the open-ended abilities and bonuses either.  It's the endless FEATS and CLASS ABILITIES and the SUPERNATURAL ABILITIES too.  Tons of 'em.  Why have classes at all?  Just give people a list of abilities and feats and powers.  Just play superheroes.  That's what you are trying to do anyway.

Finally there is the problem, again caused by open-ended ability scores and bonuses, of focusing on a single ability above all others to achieve a supreme mathematical advantage.  A wizard, for example, or a sorcerer, simply has no chance in melee combat.  There is little point in engaging in it when the monsters are beefed up for the arms race but they are not.  To compensate these casters put more and more focus on their casting stat (intelligence and charisma, respectively) becoming highly proficient in a single area at the expense of all others.  High intelligence and charisma means bonus spells for these classes and their spells become more potent.  Naturally GMs must compensate to keep the game interesting (read: challenging for everyone).  Now some bloody kobold, always the starter monster for a new adventurer, is a 10th level shaman (sorcerer) or maybe even has a kobold prestige class designed for NPCs.  Sure, it adds flavor but for whom?  The GM?  He's the only one that is going to take the time to care.  The PCs are going to start their kobold killing routine because that's where the experience and treasure live.  Congratulations, you've made kobolds a threat to 5th level characters.  Proud of yourself?  There are other monsters to threaten 5th level characters.  We are never going to get to the Purple Worm if you keep doing that.

Oh, thank St. Cuthbert, it's not a toothy asshole anymore.  Whew.

When you take all this ubermath and combine it with far, far too many base classes, core classes, and, Torm help us, a metric asston of prestige classes (I hate prestige classes) you end up with far too focused characters with far too much math in a game that is supposed to be about heroics, or at least the chance to become heroic, and fun.

So sod it.  This is why there are so many Retroclones out there, by the way.