They definitely overvalued the effect of 1 damage to all enemies in the core set.
Spiderman's Swinging Web Kick is still used as the baseline for signature damage events tho.
So, Giant Stomp is clearly above curve but it is clear that this was done on purpose. They said on stream that because his events are form locked, they are more punchy.
The 1 damage to all minions is a situational effect and hard to get actual value from, so I think the card is fine.