First, a question: do you like apples?
Let's take a level 12 human monk in a high powered campaign (32 point buy), her base stats are 14 str, 15 dex, 13 con, 8 int, 17 wis, 8 cha. She gains two ability scores, turning those stats to something like 14/16/13/8/18/8. With VoP ability enhancements, she'd get +4 wis, +2 dex. The wizard can cast mage armor on her or she can take a level of sorcerer and do it herself
Not with an 8 in Charisma, she can't.
Let's tally up her AC! +8 Exalted Bonus, +4 Armor Bonus, +1 Natural Armor, +2 Deflection Bonus, +6 Wisdom Bonus, +4 Dexterity Bonus = AC 35, Touch 31, Flat-Footed 31. And on top of that, she has DR 5/magic. Most dragons aren't so blessed with this kind of unkillablilty.
Scintillating Scales (turns NA bonus to a deflection bonus. Dragons get a large amount of NA, right?). Wings of Cover (immediate action for total cover against 1 attack, spell, or AOE effect). Ruin Delver's Fortune (you know what that does).
A CR 11 Adult Dragon with one class level in Sorcerer is a CR 12 threat. It casts spells as a 4th level sorcerer, so guess what? Let's tally up her AC! AC 27 (-1 size,+18
natural deflection), touch 27,
flat-footed 27. Add on Mage Armor for a +4 armor bonus to AC, and Shield for a +4 shield bonus to AC. AC 35, Touch 27, Flat-footed 35.
There's the option of having the other 2nd level spell be either Wings of Cover, Blur, or Mirror Image.
They can also fly, which adds to unkillability by preventing people from reaching them - people like VoP monks who can't fly.
Incidentally, the attack bonus of the dragon would be +27, his HP would be 241, and his saves would be Fort +17/Ref +12 /Will +15. The monk's attack bonus is +11/+6, has about 70 HP and her saves seem like they will be Fort +9/Ref +11/Will +13.
I'm not saying VoP Monk is a powerhouse compared to spellcasters and whatnot, goodness no. But in terms of controlling the frontline, a VoP monk can do everything and more that a beefy paladin in a full plate and tower shield wishes she could do, but at double the speed and no armor restrictions and penalties.
What does the VoP monk do to control the front line? Damage? Tripping? Grappling?
From what I can see, the VoP Monk doesn't have the strength to
matter; it is no more than a speed bump that can be easily sidestepped if you're on the ground and laughed at in derision if you happen to be some sort of flying, fire breathing lizard with spellcasting.
So, how do you like them apples?