It's great that I get to have a pet cat or dog, but frankly they're just a burden. I give them water and pet them every day, but I don't get any return. "But Cortez, that's exactly what cats and dogs are like in real-life!" Yeah, well guess what Stardew Valley isn't? Anyway, why not get them to occasionally bring you some sort of random gift? A forage item or an artefact maybe.
I had an awesome idea for the dog, but it doesnt work as well thematically with the cat. Basically, if you use (not consumed) an item on your dog, he'll track down a person who "loves" that item (the person can be random). The effectiveness of this can be based on hearts, with him sometimes wandering to random places. With enough hearts he can start tracking down people who just like the item. maybe the cat acts as default scarecrow based on the amount of hearts. I'm not too sure, cats seem less useful in general.
They do have a purpose, they make me chuckle everytime im farming and see the cat just loafing on the ground looking grand! and the dog runs into walls... just like my real dog... oh and lets not forget that derpy face, so adorable... they might not do much, but they sure make working on the fields a lot more entertaining!
Attack Pets! Take them with you in the mines and let them kill that annoying monsters for you!! Friendship level could act as a "health", as in more they like you, more hits they take before retreating to your farm for a day.
I think it'd be nice to be able to assign them a chore that they would do until you changed it/retrained. Keeping away crows, retrieving a forage item, retrieving a fish, watching the animals so they feel safe (and happy), or visiting a villager and getting friendship points for every day the animal visits. Probability of them actually doing the task could be tied to heart value, maxing out at an 80-90% chance at full hearts. Edit: Changed 'sad' to 'safe' which is the word I meant. Losing hearts as a pet 'benefit' wouldn't be much of a benefit.
Cat/Dog shows up at Penny's "doorstep". She's playing with them. You show up. Cue adorable as all heck cutscene between the two of you. ...rinse repeat for all the other characters. YESSSSSSSSSSSSSSS I WANT THIS. This could be what happens after your animal visits a marriage candidate X number of times. As for the rest of it...I dunneh...but having them there to potentially help build friendship points would be great. Especially if you could see them around town "playing" with the person at moments when they're not doing anything (Haley standing near the CC, Penny sitting on the bench or on the grass near Haley's home, etc.). ^^
