Pet levels
Once you charm a pet I feel it should start at lvl 1 and level up through battles that way not all pets are “equal” (I know each pet is different and has their own perks)
It used to be like that in the first Guild Wars and you can raise them differently , Dire or hearty . Dire pets had low hit points but had high dps , hearty pets were bigger in size and was used to tank or soak up damage . I like your idea , but I don’t think it would go well with the GW2 fanbase .