WTF, mates.

[Wyrm]

But with all of that, would I have the necessary defense to fend off the stronger minions of evil? Or would I need to get a defiance mercenary as well?

The simple answer is no. If you want to tank with the sorc, invest in Energy Shield and Telekenesis.

Vengeance is a good skill, you can use it to cut through any immunity in the game, but it only hits one enemy at a time, so you're going to need a high/fast block shield and good resists or you'll be stunlocked into death.

Charge is only really useful in pvp because you have to concentrate mainly on that one skill and its synergies and ignore others that you would normally need for pvm. Astronomical damage though.