ecirphsoj wrote:
Voidwalker is rarely, if ever, used in parties
FTFY. I use my VW all the time while I'm grinding or farming on my 70 warlock. The only time the big blue blob isn't out is if I'm in a group. Felguard's great, for sure, but I just can't seem to keep him alive in an instance, so I changed over to Affliction.
Sethy wrote:
There are no "lower level" demons.
Each one of them have their use in certain situations.
QFT. Imp's great in parties due to his Blood Pact buff, and for Affliction warlocks with Dark Pact, an imp in passive with Phase Shift makes a great mana battery. The VW is your best tanking pet, and can be a lifesaver if you get swarmed thanks to the Sacrifice shield. The Succubus is the second-most useful pet in groups, thanks to her Seduce crowd-control ability, and she puts out decent DPS on her own, too. The Felhunter is used a LOT in PvP, since a well-timed Brain Lock can be devastating to a caster; he'll see use in PvE against casting mobs as well.
IMO, the only really useless demons are the Infernal and the Doomguard. Both break free after a time, and the Doomguard is a huge pain to summon in the first place (get lucky with a Curse of Doom, or sacrifice a random party member with the Ritual of Doom and risk dying yourself and being unable to enslave the incoming, and rather angry, demon).
Again, the pets aren't arranged in "levels." They're just spread out so a player gets some time to get used to how they work, and they are received more-or-less in order of complexity of use (as in, the imp and VW are really simple to use, while the Felhunter is a bit trickier). By the time you get the Felhunter, you should have a pretty good idea how to play the warlock class, and should have at least some idea of what situation each demon's useful in.