I just built a synergistic PM/EK Magus/Primal and jacked my summons up with everything I could grab. The Primal Ally, T5 in Primal Avatar, lets you have another summons (I also had the Magus Lich). You can Quicken cast it a short distance in front of you, and the cooldown is only 20 seconds, and it grabs a lot of aggro. The Dryad can heal, which, when combined with the shared Mantle, means she's also casting Cocoon every now and then. My skeleton acted as the tank with over 3k HP. I just set up AOE dots to support all the hires. My crazy-legs lich just ran around doing whatever crazy-legged liches do. They all shared my spell power, and all got bonus hitpoints from my Dwarven PM/EK (edit: from Natural Shielding). Use Otto's Dance Now or Else spell to lock up reapers and most champs. I only jumped into combat for the occasional Eldritch Strike and Arcane Siphon attacks to boost everyone's spell power (+60 total). I didn't have a hireling, which would have just been more icing on that cake.
Between levels 10-25, summons, pets, and hires lack usefulness with only minor utility (heals, mana batteries, door openers, etc.). After you can start getting those MoE and PA Destinies, they start to be a force to reckon with.