Limited Mobility?
As it turns out, turrets are not currently considered a “good” part of our DPS and healing. I understand the preference for DPS is some combination of a grenade kit and self-buffing, such as using Elixir B and the Utility Goggles. Many people also reserve at least one slot for a stun break—the aforementioned goggles, Rocket Boots, Elixir S, or Elixir R.
The Healing Turret is used for healing, but most people pick it back up immediately as doing so reduces the cooldown by 25%, and people like having a strong, instant heal on a 15-second cooldown. Few people regularly use the healing turret as an actual turret.
What I, personally, have found turrets useful for is providing a brief distraction or nominal DPS while I feverishly Med Kit myself during story missions where mobility isn’t a contributing factor. In other words, I use them only when I cannot run away but want to.
What do you expect? Of course playing turret builds limits your mobility but makes you better at defending an area. If you wanted to summon a group of units that stay with you, why dont you play as a Necromancer.
Turrets make you a god of your immediate vicinity. if you don’t wannt to pick up extra adds, don’t drop long range turrets.