Is there a big difference in being able to kill a mob between a tank with a healer merc versus a tank with a wizard merc?
I think you'll have to probably test it yourself to get the information you're asking for. No doubt it's going to be a lot quicker with the wizard (since the healer mercs don't do any damage), but you'd have to factor in how much time (if any) you need to spend healing up between fights.
Doesn't matter if it is two boxing or a two NPC group, if at all possible add a wizard NPC. Soon as mob gets to 50-80% health, the wiz lights it up and it drops like a bag of dirt. They have outstanding mana regeneration and seldom run out. Trick is getting the mob to that 50-80%. I do mostly run healer/tank mercs over a wiz because it is less intense and gives me a chance to relax. If you are trying to grind experience or AAs and are running someone who can heal, wizard merc is the way to go.
There is a huge difference in the speed in which they die. If you're an sk/paladin and can go without a cleric merc, then it's a no brainer. Even if it only dies 10% faster.. that's 11 mobs in the span of 10. A 100 sk runs about 7k dps, a wiz merc on burn is around 26k. So if you run with a cleric, you do 7k damage per second, with a sk + wiz merc over 32k. So you kill roughly 4-5 times faster than with a cleric merc.
