The main thing wrong with Spell Snare is that it is a one mana counterspell that when you are on the play does nothing against a one drop from your opponent
In a deck like this, the best removal spells are the ones that are stapled onto big creatures
This puts another counter on the Terror, and you rinse and repeat to pick off your opponents and make an infinitely large Red Terror
If your group is full of people who love to stack up value town creatures, this is meant to put a stop to it while also making you the player at the table they want to get rid of the least
Serialized cards generate a lot of hype, and the chance to open them will be a good driver of pack sales for WotC
My flight of adventurous dragons also included Young Blue Dragon and Young Red Dragon (there is no Young Green Dragon), Dread Linnorm (a Snake Dragon), Sailor's Bane (a Dragon Turtle), Sword Coast Serpent (a Serpent Dragon), and Fang Dragon (sadly, just a Dragon)