Let’s use Hoggies for example:
Minor perks:
Breather use accelerates cooldowns.
damage boost against targets within active Pig Pens (allies included).
Major perks:
Landed Hooks and damage dealt accelerate Breather recharge.
Damage dealt to targets within Pigpen accelerate cooldown/resource tick-rates (allies included).
Notice how no matter what combination you choose among these perks, they still find a way to compliment one another while still being valuable on their own, as well as promoting new strategies? I think every perk tree for every hero should be given the same design philosophy. The promotion of new strategies and new synergies would be even more engaging and dynamic than it already is. 