It would SUCK in DDO. VoP works best in low-magic (few magic items) games and in normal games for people who don't want to bother with loot. In high-magic games (or ultra-exaggeratedly high magic games like DDO) people with the Vow fall way behind everyone else. As written, you'd have worse AC, ability scores, saves, HP, SP, melee damage, no ranged attack, weaker spell damage/DCs and no utility whatsoever. Also, almost no way to bypass any DR that relies upon alignment or special property.
Besides, one of the number one reasons to replay a quest in DDO is for loot. Without that drive, the devs would have to produce, not dozens, but scores of quests for every level beyond what is already in the game, and just so that Vow players wouldn't get bored almost immediately.
Cool idea in/on paper, awful idea for DDO.
Useful links: A Guide to Using a Gamepad w/ DDO / All Caster Shroud, Hard Shroud, VoD, ToD Einhander, Elochka, Ferrumrym, Ferrumdermis, Ferrumshot, Ferrumblood, Ferrumender, Ferrumshadow, Ferrumschtik All proud officers of The Loreseekers. Except Bruucelee, he's a Sentinel!
I've hoped to see some of the multiclassing feats in DDO, but with certain posters and their well know opinions on Monk splashes and sometimes "non-pure" classes characters in general, I would expect the furums to melt down from the wailing and gnashing of teeth.
The minute someone makes a Monk 2/ Sorcerer 18 with Ascetic Mage, min Wis and Maximum Chr, I would expect their heads to explode.