I have been wanting to make my own foundry missions for some time. I Have needed several featured active for some of them, one being the ability to Disable star ships in space combat. Another feature I have been needed is the ability to create my own Alien animals or creatures (non sentient).
Allowing me to take a basic frame skeleton which determines how they move. Then Allow you to attach a number of parts like arms, legs, tail. Also give them their abilities, like a ranged weapon like venom, resistances, weaknesses, and behavior... Ranged, Melee, Defensive, aggressive...
The ability to have ships/ground troops disabled instead of destroyed has been something we've wanted in the foundry for some time. It's possible that it may come with Season 6 but I wouldn't hold your breath.
As for the creature creator... no... or at least not anytime in the foreseable future is it qould require this tech to be implemented in the main game first. I would like the ability to customise things like melee or ranged groups, energy weapon types and general skillset packs but well we'll see what's on the board for the foundry later.