Pets are actually fine in normal until way into act 3. You just have to buy damage gear for them, and support a little.
One of the things I like about +skill gear, mastery shrines, and mystics for pet classes in this game... they allow multiple strong pets to exist at a relatively early part of the game.
When a 42 level Soothsayer reaches Delphi in Epic, he has access to a mystic to rearrange his skill points. If he wants to see what life would be like with a fully developed wolf line, lich king, and ternion build... then he could rearrange skill point into a pet build, cast the pet, and then respec into a different pet line. Since pets tend to stay alive longer in epic and legendary while dealing more damage than they did before the fanpatch, you could play an entire gaming session with that configuration. A relatively low level Soothsayer could have a full line of very powerful pets AND a powerful ternion attack using that method. It would cost money to respec the skill points, but the cost caps out at 45,000 per point... so the cost of respecing gets relatively cheaper as the game goes on.
Mystics and mastery shrines give pet users, like Soothsayers, a way of temporarily boosting skills in order to summon a relatively permanent uber pet long before it might have shown up "naturally". The pet will revert back to a weaker version if it has to be resummoned, but post-fanpatch pets stay alive much longer than they used to (especially in epic and legendary). Just a way of using an in-game dynamic to give the Soothsayer and other petmancers an edge.