Horobi, Deaths Wail Creatures dont last long when Horobi, Death's Wail is on the battlefield
Magic becomes more of a game about accounting and resource management with each passing year and thats something Atraxa, Praetors Voice interacts with very well
Once a ward ability of another Frog has triggered, causing it to lose ward by removing Long River Lurker or changing its creature types won't affect that ability
While it could use some protection (enter Temple Altisaur), being able to discover X once per turn based on the toughness of a Dino entering the battlefield is a huge play, and one that can snowball into an easy victory if your deck is stacked the right way
Winter Orb is a "stax" artifact that severely limits each player's ability to untap cards during their untap step, and that will slow the game down
If you have several possible ways to Sacrifice a creature, only one takes effect