Curious Question About "Pets/Tools"

After finishing a game as Fizz against a Heimerdinger (first time Fizz; counterpick; I hate my life sometimes), anyway, I realized something that got me wondering.

In regards to Champions and their "pets/tools", I'm curious about this one thing? Why is unable to "command" her plants? As far as I'm aware, the only way for her to do so is by auto-attacking her opponent.

- Though, to a lesser extend of direct command, can simply move around to somewhat control what his stars hit. - Can command his soldiers to 'attack' without necessarily putting himself in range of the target or make them 'charge' in any direction he pleases - Chooses where his barrels go, as well as, when the detonate (assuming an opponent doesn't break them first) - Can auto-attack you. as well as, fire rockets and/or throw grenade(s) at you. - If she jumps you, her tentacles jump you, everytime. - All of her abilities "command" Pix to do some type of buff/debuff of her choosing. - Tells his pets who to fight by placing his aids E ability on them. - Literally commands the ball with her abilities. (It's even in the ability names) - She summons the balls, she the balls where to go and when to go there. - Tells his ghouls who to focus with his E ability.

The only other champions that somewhat matched Zyra's situation are:

With this being said, I'm just curious as to why Zyra and these few champions have such low "control/command" of their pets/tools? Is it a balance thing? Is it an overlooked thing? Is it possible to give them more control/command, later down the line? Or are they meant to be this way for other reasons that I am not noticing/realizing?