Necro and Game Comparison Questions

I recently started reading about this game, and if I decide to play I know I will definetly want a Necromancer. I've just always loved Necromancers.

The spells that interest me the most are the Death magic spells, especially those that raise corpses into minions. But reading around a bit I've seen that many people believe that this type of Necromancer is inefficient in PvP since you only have 8 people per side and corpses are rare. Is this so?
And if it is, can you use summon spells for PvE and then maybe switch your spells around and use non-summon ones for PvP?

And another question, which I hope I'm allowed to ask. Is there anyone that has played both Guild Wars and World of Warcraft that can give me a comparison? I have played WoW for many months now, but am tiring of the lack of improvement to the many bugs involved with my favourite class, Warlocks.

It's true that in PvP you can't depend entirely on "exploit target corpse" spells. I usually don't bring more than 2 or 3 of them in PvP. Honestly though, a few minutes into the battle there are usually corpses to be found, especially considering that players usually die multiple times in PvP because of resurrections.

And yes, you can change your skill set. The way skills work in Guild Wars is that you have a certain number of skill points, and gain more with experience. Each of these allows you to acquire one skill from a trainer, who you can find in towns. This system allows your character to have access to any number of skills, but when you go into a mission or a PvP battle you can only take 8 of them. You can change this skill set anytime you're in a non-combat area (towns, mission staging areas, etc.).

The problem isn't just that corpses are rare- they're the scarcest resource on the battlefield, and in addition to that, you'll be competing with opposing necromancers trying to use them, as well as stepping on the toes of any other necromancers on your team that might want to use them.

Corpse scarcity isn't even the major problem, however. The conceptual flaw in the death necromancer is that minons define the idea of "too little, too late".
When you're matched against an opponent of equal skill, there will be a big struggle to get that first kill, to get the ball moving for your side. As a death necromancer, half of your skillbar (or more) will be useless for that decisive part of the battle. Having 4 minion spells does nothing to help you seize the advantage; it simply keeps the ball rolling once you're already winning.
Not only that, but minions are rather pathetic, from what I've seen. They do pitiful damage to a level 20 character, and any experienced team will simply ignore them for targets that are actually threats. Their best purpose is in bodyblocking and causing a little chaos on the battlefield- minions themselves can't do much on their own.

Most of these issues are moot in PVE- have a teammate get the first kill, then start raising an army. You can bring them from one encounter to the next, if you have the right spells to keep them alive. Corpses and enemies are plentiful in PVE, so you really shouldn't struggle to form a small army there.

Instead of making a new post, Ill ask my question here: Does anyone know how many pets you are allowed to have up at one time? I plan on making a R/N PVE character for pet and life drawing purposes. Any help is appriciated.

EDIT:
Im not looking for build suggestions. Just wanted to get that out before the post is flooded with them.

one at a time

get rid of one you dont want anymore at a animal trader

necro minions are separate and i do not think there is a set limit

some have raised small armies

A Ranger's pet? One. Necromancer minions? As many as you can raise and keep alive.

So is death magic worth having in PvP without using the minion or corpse exploiting spells?