With the current implementation of Dodge, AC, and PDR, it makes it difficult to pull what you need to on a Monk tank (if it is 12 Monk fighting centered, or 20 Monk pure.) Yes, Earth stance gives some PDR, and epic destinies can enhance that, but you end up with much lower than any Fighter, who will have more HP normally. With all the enhanced armor bonuses from Defender stances, they should do something to put Monks on par. My thought was to make it so Monks, while centered, get a half your Dex mod bonus (or Wis bonus, as you feel fit) to dodge, while centered. This should put Monks somewhere back on par. (it will also help Dex Monks actually have useful dodging, and some defense to everyMonk.) Yes, at first glance this may look absolutely overpowered, but think about it. Even a Dex Monk can cap out Dex at, what...
18 Base + 6 level ups + 3 enhancements + 8 item + 3 Insight + 1 exceptional + 4 tome + 4 stance (though who would be using wind stance to tank?) + 2 ship buff + 2 bard song + 9 Destiny (maximum possible Dex obtainable through destiny) + 2 yugo = 62. (+26)
which is + 13% dodge, yeah, that's a bit much, but its also the extreme.
Basically what it would do is allow Monk tanks to have a respectable dodge (higher than those Fighters in fullplate) that scales with a stat. Now lets look at the 'normal' Monk tank.
15 Base + 2 tome + 8 item + 2 insight + 2 ship buff + 2 Yugo +1 Exceptional -2 stance = 30.
That's 5% dodge, which lets say wearing a +3 and +4 dodge item, with the feat and Monk dodge of course = which leaves you at 21%. I don't see this as unreasonable, as that's what a Monk tank should be about anyways.
My other thought is a Wis bonus to PDR. Wisdom makes you dodge better, perhaps it also gives you a resolve to stand through blows. Again, this would be based on your modifier (perhaps directly this time), and would allow a Monk to stand through more hits, more easily. If you added so a Monk got 1 PDR for every 2 wisdom points, they might be more in the running compared to Fighter's with their heavy armor. (who's PDR scales off of BaB)