I'm playing a W/N myself right now, and having a great time with it.
Some thoughts:
1. In thinking about weapon upgrades for a W/N, I definitely prefer a zealous mod to my weapon. Necro spells tend to be expensive enough that I want to have alot of energy on hand. To that end, I end up using a zealous mod on a sword or axe, which have a faster attack rate than a hammer. I've had fun playing a hammer warrior before in PvE, but it may be better for this class combo to use a faster weapon.
2. I've had the most fun using the curses line at the beginning, and spreading more into death a little later. You can get Enfeebling Blood at Grenditch, and Shadow of Fear in the Eastern Frontier. These are great skills to use if you've gathered aggro around you - your enemies' attacks are cut in half, and when they hit, it's with a 2/3 damage reduction. Consider these preventative measures, as opposed to the healing spells you're using in the blood line. They not only help you, but your other party members as well.
3. Mark of Pain is good, but it makes aggro managemnet a bit trickier. If you're going to use it, use it with Flurry and a zealous mod. Flurry will let you get more attacks in more quickly, but at a reduced damage. While the damage evens out for your target, you end up doing more damage to his buddies. And if you're using your zealous mod, you'll be charging your energy back up more quickly as well.
4. In the Northern Shiverpeaks, you can get Rotting Flesh and Necrotic Transversal. Cast RF as your opening shot, then gather aggro. You should have 3-4 guys on you, all with 4 pips of degen. Concentrate on taking one down, then cast NT. You'll teleport to the corpse (which is adjacent to you), and now the remaining baddies have 8 pips of degen, at least for a few seconds, then down to 4 again. Anyone you're bleeding with your sword could be up to 10 pips. This makes them nice and soft for the rest of your party.
Caveats - Stone Summit Howlers will send your disease/poison/bleeding right back to you, so they have to be killed first. Also, human parties don't always want to wait for a warrior to cast a spell as a lead-in to battle. If you're henching, that's OK. Also, as you progress further into the game, 8 pips of degen will mean less, and more enemies will be resistant to these conditions, or throw them back at you. However, spreading conditions around like that does work nicely with Victory is Mine!, for a nice self-heal / energy refill. Oh, and if you party with any necro primaries, be sure to discuss corpse usage before you go out. They may be willing to give you the first one, but that's about it.
5. In the Northern Shiverpeaks, you can also get Bonetti's Defense, which not only protects you, but also gives back alot of energy, letting you utilize your necro spells again!
Hope that helps. You always have the option of packing more warrior skills for a particular area, but the necro spells are of such great use that it's hard to ignore them.
Have fun!
