Best class with Warrior merc to molo...Follow

I like the ninja class with a warrior merc. reason: they are very very sneaky and they get all the phat lewts

Shamans get a FD now?

it only has 2 charges, not to mention a ton more rings out there that are better by a long shot.

If you actually plan to use a tank merc primarily, then you really do need a class that can sufficiently heal said tank. Ideally, one that doesn't already do the tanks job better than it does. IMO, Paladin is right out. I've *never* used a tank merc as a paladin (I have one, just because, but I honestly have never pulled it out). It's a complete waste of time. If you can heal the merc, you can heal yourself (and paladins actually get several heals specifically designed to make it easier to self heal while tanking). All you're doing is minimizing your kill rate doing this. Couple a paladin with either a healer if you're taking on nameds and really need the extra healing, or a caster for extra dps (or often, none at all when plowing through undead where a merc will just slow down your exp rate).

I'd also shy away from cleric. While it might seem to synergize well with a tank merc, you'll also run into the "slow kill rate issue". You'll probably find that in most situations, the cleric can tank and self heal, and would be better off with a caster for damage. I've never played a cleric though, so this is really just theory. Someone who plays one might have a totally different answer.

My assumption would be that druid or shaman would work best paired with a tank merc. They have sufficient heals to keep the merc alive, and tons of damage and utility (especially the shaman, who'd be my first pick) to make the pairing work. Which you choose is really up to what you want to play.

Be aware that you don't have to just do the hot zone daily that's in your level range. That's an approximation of the level of the zone/mobs you'll be fighting. Sometimes (most of the time!) you'll want to blow through the previous couple level range dailies. Oceangreen is a pita for dailies given the way the mobs spawn and how spread out they are. But assuming you're running an heroic paladin (guessing here), I'd strongly suggest in addition to doing the Old Bloodfield daily (which is actually going to be pretty tough at level 85), spend the time running to Hills of Shade. Very very very good paladin hunting areas. Specifically, the blackwaters and the fishermen are awesome. Probably the best paladin hunting spot in the game in that level range. Long run to get there (but not too bad with fast paladin mount). Well worth it IMO.

The next level up in terms of nicely groups undead is the HoT zones (feeroot really). But man is that mediocre exp for effort. Enjoy the relatively easy blackwaters while they last IMO. Also, don't get stuck on the idea that higher level is better. You'll find that plowing through a large number of blue or lt blue mobs will net you far more exp over time than struggling to kill whites and yellows.