When talented, geared and buffed my VW has over 50K HP. Tanking 1 elite is no problem, I've solo'd every world group quest elite and quite a few other things like Thrym in Zul'Drak and trash in normal Gundrak easily. 4 of them should be able to tank heroic trash and hold aggro off the healer np, just pick up 1 elite per VW and you're golden. If it's more than a 4 elite pull (quite uncommon) you can probably nuke 1 elite down before it kills you. To kill the trash you just need to figure out how long the VW needs to generate enough threat so that SoC spam won't pull it off before stuff melts. Heroic bosses might be a bit tougher, because of aggro drop mechanics.