Stadium 2 has the overall better lineup of minigames but Sushi Go Round is the best of either of the games and possibly the best minigame I've ever played in my life
Every other minigame in Stadium 1 is pretty simple and barebones but Sushi Go Round has way more complexity and strategy and excitement than any of them and it's surprising that it even coexists with something like Clefairy Says
Sushi Go Round BY ITSELF is better than half of the Mario Party games