Skill is far less effective on Non-Sorcs as they all suffer a much higher risk due to no healing. Sorcerers though don't need Vengeance to be amazing as they have other builds such as super tanky.
I guess you couldn't convince me to use Sorcs despite the factors you've listed.
But really, should I went to the hassle of being Sorc to get Vengeance only? --- OP tomes, high Res, and skills be damned; I won't use Sorcs. R - Rocket Scientist | Official Trumpeter of the SMTIV board
The ultimate synergy Vengeance has is with Vantage. Vengeance requires low health to get the most, and Vantage makes sure you get your painful hit in. Unbeatable when you're using Nosferatu/Aversa's Night (especially when forged). Wrath isn't as necessary. Or at least I haven't needed to use it. Limit Breaker and Armsthrift take massive precedence.