Do you know what I wish for is that Heimer is like kled in which his Turrets get all of his main bonuses. Such as Health and Attack speed and Damage. Can you picture a heimer turret going off Damage and having 2.5 attack speed. Have it set that as long as he has a Turret "ACTIVE" he becomes invulnerable until it or they die and he is able to be attacked. That just seems like fun.
Just change his kit to be all about his turrets. Q is the main damage turrets that can scale off attack speed but have a shorter range. W can be a turret that has a longer range but has a slower attack speed. E can be an AOE shot with a short range with a slow effect. His ult can stay the same since it's just a beam cannon.