I can't seem to find any reasonable suggestions for pets that have good damaging stats or am I misunderstanding how pets work with damage and crits? I'm a level 35 Fire Wizard looking for a long-term pet.
Starting a new pet from scratch can be a bit tough. I'd suggest finding any fire pet that gives a fire blade card in the kiosk, and starting from there.
There's an advanced search function that lets you search for specific talents in the kiosk.
For a good base fire pet, you should probably look up Spell-Proof, and Fire-Dealer.
The value of the attributes correlate to the max stat each talent gives. (255, 250, 260, 260, 250 is max stats). Fire-Dealer with max stats gives 10% fire damage, while if your stats are a bit below(around 245), you'll only receive 9% fire damage.
There's a lot of good pet guides on youtube you can find.
For the 5 ideal talents on your pet for questing and in most situations, I'd look for Fire-Dealer, Fire-Giver, Pain-Giver, Spell-Proof, and Spell-Defy. (These talents together will give you 22% fire damage, and 15% global resist).