Higher touch AC has limited benefits, as they could already hit the target on full AC. Take any 3/4 BAB class with their attack stat at a secondary 14, at 5th level you're looking at a naked +5 to hit against a naked touch AC of 16(and full AC of 16) versus the guy in full plate with an unenhanced touch AC of 11(and a full AC of 20). Then you look at full BAB with a primary stat at 16, and they'd be swinging for +9 accounting for masterworking.
Now consider, the Monk is primarily a melee combatant that makes use of full attacks, with his higher speed, he is likely to be the one first engaging. Therefore, he will be exposed to at least one attack against his full AC, possibly a full attack. For any full attack dependent combatant, you require sufficient AC to come out of an exchange with your skin intact, and at least give as good as you got. Then you add in that the majority of published creatures and encounters target regular AC rather than touch, and the result is obvious. A character must be able to resist common attacks effectively before attempting to resist uncommon but powerful attacks.
Automatic increases to damage also don't really mean anything. Every class has an automatically increasing source of damage, and they largely increase at a better rate than +1/4 level. Note also that BAB contributes twofold to damage, accuracy is a factor, as is the damage conversion provided by feats.
Full BAB classes as mentioned, can convert their attack bonus to damage at an effective rate, reducing their attack bonus to that of a 3/4 BAB class, with a primary ability score in Str. Additional bonuses to these classes go above and beyond, Barbarians(rage), Fighters(Weapon Training + the specialization feats nobody else has the excessive feat slots for) and Paladins(smite) are notable for hitting like trains specifically because of their added damage.
3/4 BAB classes cannot afford to rely on BAB and primary iterative output, which is why they are either fullcasters with melee secondary(Cleric, Druid, Oracle), have their own mode of non-melee contribution(Bard, Inquisitor, Alchemist Summoner) or possess rapidly scaling damage boosters(Bard, Rogue, Alchemist, Magus). The Rogue gets an average +1.75 damage per hit per level, as does the Alchemist(who also gets a stat bonus from mutagen and any attack boosting Extracts), while the Magus as a spellcaster gets a low +3.5 damage per round per level on offensive spells.
Naked performance is also a poor benchmark. The whole point of Wealth By Level is that your abilities are directly correlated with your equipment. AC, Saves, attack bonus, ability scores, all of these renders your character statistically a level X character. A naked level 20 monk has the AC of a level 6 monk for a same type comparison. Thus the ability to spend wealth efficiently is a major determinant of power.
This is one of the reasons why TWF and Unarmed Strike are sub par, they simply cost more to equip on the costliest item types. It's also why heavy armors are efficient, they supply the first 9 points of AC at the cost of merely 100gp per point, and MAD characters are not efficient. The most wealth independent characters can supply all these bonuses by themselves over an extended period of time. Clerics, for example, would hugely offset the cost of enchanted weapons and armor by dint of Greater Magic Weapon and Magic Vestment, allowing funds to be dedicated to further bonuses or even premature mainstat boosting
The 3 basic ki abilities are indeed swift actions, but feat chains and archetypes that make use of ki or stunning fist(or variant) usages tend towards standard actions.
Finally, competence against spellcasters is significantly overstated. Presuming even a favorable scenario(spellcasters within easy charge range), Monks are weak against summoned creatures, swarms, miss chances(fog, mirror image, or even darkness), autohit attacks(magic missile), DR, invisibility, battlefield control and for divine casters, their AC itself. A 3/4 BAB class with MAD just isn't going to do that much good against Medium armor and a long duration buff spell.
Of course, pretty much any martial class is going to have trouble against a spellcaster who knows they're coming, but Monks do especially poorly, because they lack any major strength to overcome such obstacles.
