Dunsparce... I have never played during its era. But in the context of right now, and the SUM-on rotation it will be used in, my critique:
- 50 HP and 1[C] retreat is quite problematic. After you use its power, it becomes a bench sitter prone to snipe knock-outs. Mr. Mime will rotate, so bench protection will require an evolved card.
- While going second to use the attack is strong, I don't find many advantages it would give versus the player going first. Your opponent can still use Tapu Lele for Pokemon Fan Club and other supporters to develop before you do - and given that you used your first attack to develop your bench, it sets up your opponent to deal damage first.
- As of late, there just aren't many basic Pokemon SUM-on that can disrupt opponents with abilities when they become active. Wobbuffet is rotating, too... Well, I guess you could try Goomy, but then again, watch for Alolan Muk and Guzma be everywhere, given that Garbodor and Float Stone will rotate.
In other words, the card might have been strong in one metagame, but think about our future one: It may help budget builds, but it won't as effective as before.