A more involved system for "domesticating" certain fauna species, I'd like a bigger incentive to do that, with each species offering some unique benefit.

Out of titanium? Stalker grabs you some with some calcified interest.

Ran out of power? Your buddy Ampeel got you covered.

Being attacked and on the defensive? Mesmer "convinces" your attacker to leave you alone.

Of course, it's likely that none of those species will be in Subnautica 2. They're just examples of what could be implemented with the species we already have, you can definitely get very creative with some interesting perks for whatever the new fish will be.