That can be pretty powerful, especially if you have a lot of food
If we get a card that gives you an energy counter when a creature attacks, this could be potent
If the creature that entered the battlefield leaves the battlefield before evolve tries to resolve, use its last known power and toughness to compare the stats
The Great Aurora lets you do something with that, for example, just off the top of my head: Creatures (23) 4 Elvish Visionary 4 Elvish Mystic 4 Courser of Kruphix 4 Satyr Wayfinder 3 Den Protector 4 Nissa, Vastwood Seer Planeswalkers (3) Lands (22) Spells (12) This isnt tuned at all, but the plan is just to get permanents onto the battlefield as fast as possible
What if creatures much more powerful than FrogmiteFrogmite or Myr EnforcerMyr Enforcer could be given affinity for artifacts
Where this card excels is the fact that it gives goblins haste and a nice bit of cost reduction