Why do a conjurer's pets not hurt a group's ranking but a necro's pets do? If I had to choose which to have during a ranking session I'm going to pick the conjie pets every time. And conjurers get magic missile which is also not a horrible ranking spell.

Bear in mind, I totally suck so it's entirely possible I'm just not "doing it right" but blind, weaken, faerie fire, and maybe poison if you've got mana to spare are okay and all, but usually by the time you've got that stuff landed the thing is almost dead. You can spam chill touch, but then your damage output is the suck also.

Is it intended to be some sort of balance because liches are so ridiculously powerful?

It just seems dramatically difficult to get a decent ranking group going. On the rare occasion that I play a character that can tank or otherwise is able to get good groups I try to pick up necros because I feel bad for them, but I basically assume they will be useless for the group. 9/10 I'm right. Occasionally one will bring along a slew of damage wands which is nice, but any mage could do that.