From my experience, due to the lack of supporting items which are either very costly or rarely found, and a dependence on potions, monks can be a bit more difficult to play than other classes. A greater drop rate of monk supporting items, perhaps even monk specific items would greatly help the class. Possibly even a slight change to the class.
Obviously, monks are not supposed to be on par with fighters, but unlike the other medium BAB progression classes, they do not really have anything to make them more effective or group oriented. Even barbarians, a full BAB progression class, received modification to make their class more effective.
Clerics have buffs that put them on par with a fighter in terms of AB, AC, and Damage while still having self healing abilities. Druids also have buffs, and an animal companion, some of which can be very effective in combat.
Rogues have several skills which are quite helpful to have on quests, such as search, open lock and disable trap, some of which are very helpful on higher level quests.
Bards have use magic device which allows them to use most magic items if their skill is enough, in addition to having bard song, and items to further increase their power.
Barbarians who receive the same BAB progression as fighters can receive a massive build to both AB and damage with a specially modifier rage.
There may be drops for monks but they are incredibly rare. There needs to be purchasable- items. Just as a fighter can buy Full Plate and a Tower Shield Or a mage can buy more spells And not 2k gold for a measly 2 damage. No monk until what... 8, does equal damage than a fighter with a longsword, or a rogue or cleric.
Monks should not have AB equal to full BAB classes as they are not fighters, but they still do less damage than even the medium BAB class. . Their AB is certainly an issue, as they have very few means of increasing their damage without depending on buffs. Rogues have Low AB, but can deal MASSIVE damage. Fighters have high AB but can do nothing within their class means to improve it Clerics and druids both have lower AB but have many means to improve it. In fact druids were flat out GIVEN a bonus to their AB in the wild to nearly put them on par with fighters. An increase in AB would offset the need for increased damage, as monks would hit more, and therefore do more damage.
Every medium BAB progression class except the monk has the ability to use the wands either through Use Magic Device or due to being an arcane casting class (bards) or a divine casting class (clerics and druids) . Monks can only use potions. They have no self buffing ability. They may receive stunning fist, but it is not as effective due to a low AB. The same goes for improved knockdown, which is also less effective due to the low AB.
One of the ways in which the monk AB could be altered is to receive their wisdom score as an AB bonus. That would give the average monk a +2-3 to AB. Scales nicely with now very expensive potions. Formerly, cheap but... due to crafter whining Wise Man's Brew got the kick in the nuts
Monks already received a slight buff when it became possible to cast magic weapon on gloves, but that does not over shine the benefits the other classes have, and those which the monk lacks.
There are a wide variety of ranger, druid and barbarian only items which are not as difficult to find and get as monk items. More common drops of items that benefit monks would also be helpful. For example, 2/use magic weapon gauntlets which are more common to drop. I have not seen any such items on higher level quests. Perhaps more items drops that monks can actually us, and hope to find without being incredibly lucky, that cast mage armour, or other spells which help monks. Monk only consumables similar to bard items would also help greatly.