And much, much more. And seriously... i see the monk win in MOST, but of course not all challenges. Anything outside their classes is pretty much limited free for all anyway, so we can and should only rate in-class abilities. Expert DOES have obscure skills - and more skillpoints, (but seriously... wrestling a monk in his dreams? That is insanely circumstancial) and the Adepts has a few low-level spells. NO way that catapults him on the scale ahead, and if the monks abilities are weakish. (Yeah the freefall ability should provide movements in higher levels - spiderclimb, gliding - and yeah his self-healing should be a tick better... and yeah Abundent Step and Quivering hands should be usable more often, and he should have a DR/Chaotic growing through the levels... but STILL: Evasion, broad saves, immunities, ground mobility, combat feats... it is not THAT bad)
Really? Most? What the Monk has are crap, garbage, shit, and Evasion. Ground mobility is an oxymoron in D&D, you're not mobile if you're not flying or tunneling. Let's do a breakdown of how this all happens:
We need this for example (And most of these have to be re-evaluated for different levels... and HELL: PRESTIGE-CLASSES):
The monk and the XXX are old enemies. By chance they meet each other unprepared. They are 60 ft. apart. Who wins?
Monk vs. Expert - At low levels, the Expert can pull out a Wands/Scrolls of Entangle, Ray of Clumsiness, or Ray of Enfeeblement. If any of the above hits the Monk, the Monk is basically incapacitated while the Expert pings him to death with a crossbow.
At each progressive level, the Expert can use higher-level scrolls than the monk and can reliably use wands from an earlier level. He might also have a powerful mount or pet bear (let's see a Monk grapple THAT), or be absolutely deadly with a sickle.
Adept vs. Expert - Obscuring Mist, Sleep, CDG. The Monk can't find the Expert, and the Expert can use a wand of Sleep, if need be, to just force the Monk to keep rolling until he gets a 1 on his Will save.
The monk and the XXX are both in a dangerous, dark place. They are both prepared for trouble and will attack anything on sight. Who wins?
The Monk is, essentially, blind, unless he has Darkvision or a light source (which will bring attention to himself). The Expert can train animals with scent and blindsense and use them to guide him through the dungeon, even without light, and to alert him to danger. If he's feeling extravagant, he can burn a scroll of Darkvision. What's more, a Monk can't kill a Troll. At all. Or anything with decent DR he can't overcome, or anything incorporeal
The Adept is even better prepared for this than the Expert. He's got an animal companion that can carry a light spell ahead of the Adept and scout around without endangering the Adept. Obscuring Mist makes for a good defensive/obfuscation spell while the familiar directs the Adept's attacks.
The monk and the XXX are both at home in a city. The other dude is a thorn in their side. They need to discredit and shame the other, before seizing their assets and have them drive off. Who wins?
Expert, EASY. He has a substantially higher Diplomacy mod because Charisma is a secondary score and he has all three synergy skills as class skills. Monk has only one synergy skill and is basically forced to dump Charisma or fail at being a monk.
The Adept might lose here, because he doesn't even have Diplomacy as a class skill. That said, he can use spells like Cause Fear, Dancing Lights, and Ghost Sound to make the Monk's mansion seem haunted.
The monk and the XXX both have a fortress with guards and security-wizards. How do they enter the respective other fortress and kill the master?
The Expert has a chance if he burns ridiculous amounts of resources, but not the monk. The Adept can play the CoP game since he has Commune and enough spellcasting ability to screw over an unprepared mage, but if there's a security wizard, there's really no realistic chance that any of the three classes mentioned will ever succeed at this task (nevermind actually be able to hire security-wizards).
The monk and the XXX are in a footrace with obstacles (walls, spinning dull blades, balls shot at them, etc. while some japanese dudes laugh) who wins the money?
Nothing even remotely like this happens in D&D. Prince of Persia doesn't translate to D&D because there's a certain something lost when the success of gravity-defying acrobatics is determined by lady luck.