You can cast it as Coil and Catch for an instant-speed spell that draws three cards and discards one, and then Marang River Regent shuffles back for more potential casts just like the aforementioned Green Sun's Zenith cycle
This is extremely powerful when players have another creature on the board ready to attack, and it's sure to be a mainstay in white decks
The reason Thragtusk is so strong is that it ends a lot of aggressive strategies, specifically red ones, and unlike Baneslayer Angel, killing the Tusk does nothing to help
Nobody's paying 10 mana per creature to swing at you when there are other targets at the table
As of now, the release dates for the three Final Fantasy Secret Lair drops havent been announced yet
Thats a little dramatic, but this creatures impact is anything but