Either I am doing something wrong, or the witch is kind of weak.

I was saying the same thing and in comparison my ranger felt alot stronger then the witch (one hitting mobs when soloing) and the minions were super annoying, so I ditched zombies and have gone raise specter, supported by minion life gem and let me tell you having one minion instead of 5 really helped me. Now I am building cold damage- ice spear with the multi gem is really effect, and firestorm over head with mana regen aura just makes her feel so powerful.

61 Summoner here and doing just fine. Farming Act 1 Merc while my friends catch up.

Gear


Current Spec

-A witch? why not a wizard, cmon
-Wand? booo should of been a staff
-Fire ball should be doing more damage when its a slow spell
-Cmon burn damage Ugh not a fan of that
-firestorm muti hitter, damit should be a single giant rock hitter call meteor
-Fire trap should of been a meteor with out the dex requirement
-Int got no magic damage only mana and shield, retarded
-Most of the fire enhancement requires you to have strength, lame


From a fire wizy fan METEOOOOOOOOOOR!!!!!!!!!!

as a witch you we feel a tad weaker because your spell dependant mostly not gear dependant (while levelling anyway). You can really notice the difference if you out level the area a bit. (unless your gear is pimping).
But saying this i have tons of gear on my maurader. probably 5-6 exalts worth. and he dies all the time in act 3 merc (level 65).
But my summoner - dual fireball totem witch smashed act 3 and finishes 66 maps no worries. and she still wears blue gloves and helm. yes they are 4 link. but god her gear is trash. utter trash. Once you get life leech on your spectres its all over. my Fireballs without totem does 2k dps. the fire sentinals hit for way way more lol. with three of them and LMP and faster attacks and 2 totems faster casting and 3 fire trap totems my screen is just on fire. its quite fun.
although i will say this, the exiles that can jump or leap rape me. 1300 health is not good lol