Now, we all know critters. Those useless-but-adorable creatures we were expecting a use for in this last update. If Klei is ever planning on adding a use to these pets (I really hope so), I suggest they put it this way:
Different pet traits make pets behave differently. (No, I don't mean animation-wise.)
Affectionate: Makes the pet give off a sanity aura (to pet owner only).
Combat: Gives the pet ability to fight other mobs.
Crafty: Allows the pet to use it's "special ability" (see spoiler below for more info).
A pet with the "crafty" trait would be able to do something special no other pets could do. Suggestions I made:
Vargling: Being a baby Varg, it would be able to neutralize any aggressive hounds as long as they don't come from hound attacks or other Vargs.
Kittykit: Being a baby Catcoon, I believe it would be nice giving it the ability to kill critters by jumping on them, allowing easy Krampus farming and stuff.
Glomglom: Being a baby Glommer, It would be fitting if it would make goop every 4-5 days.
Ewecus: Being a baby Ewecus, I think it would be able to either stick your enemies (which would cause them to aggro on it) or make it brushable for easy steel wool.
Broodling: Being a baby Dragonfly, I think it should either be able to cook food for you or spit out a fire for you (the kind Red Hounds and Lavae drop when killed) when commanded to do so.
Playful: Since this trait is the one that requires paying the least attention to your pet, I think it should be the least useful trait, simply making your pet play more with itself or with others.
Wellfed: I think this trait should be removed, and instead used as a passive trait that increases your pet's max health and health regen and slows down food consumption.
I also thought of a few more pets that I can think would be really enjoyable:
A baby Chester, one that everyone can have, has 4 inventory slots. Can be upgraded with nightmare fuel on a full moon to a 9 slot Chester, doesn't get the "Combat" trait and the "Crafty" trait would make it work as an icebox as well.
A baby Hutch, being just like baby Chester, but can't be upgraded. The "Affectionate" trait would turn him into Music Box Hutch (without light), the "Combat" trait would turn him into Fugu Hutch (Again, without the light) and "Crafty" would allow him to make a small light radius, maybe equal to a Magiluminescense.
A baby Voltgoat. The "Crafty" trait would make it's horns slightly longer, allowing it to function as a Lightning Rod (but not with as much priority) and aggroing on every non-allied mob that comes near it.
Thank you for reading. Please feel free to criticize my suggestion or modify it in any way you'd like. I'd be happy to read the comments. As long as they support my suggestion :).