Monks are skirmishers, not tanks
If you play a monk like a barbarian, rushing in and taking hits, you're not playing to their strrengths. Monks are skirmishers - with their improved movement, have them circle around to casters. (Stunning blow to yet another wizard.) They get ahost of powers, some which are useful in combat and some aren't. They get all saves good as well as evasion early and SR later on, making them much more resistant to spells then others. With two stats to boost AC, you double the potential for spell or item bonuses. And of course both stats that give AC also give even better saves.
They've very effective at what they do, but what they do isn't run up and get pounded on like a front line fighter. If that's the roll they need to fill because the team doesn't work togetther, don't be surprised if they don't shine.
A quick thought about monks and point buy - I play in several games, and in all you roll stats. Point buy favors characters who only need a single prime attribute, like most casters, who can get away with lower numbers for other points (yes, Con and Dex are important, but an 18 in a casting stat and 14s in those go a long way). Monks, like Paladins, need several good stats, and are therefore fairly heavily penalized by point buy.
Cheers,
=Blue