Legality depends on the tournament format -- Summon: Knights of Round can be legal in some formats and banned or restricted in others
While Snorlax isn't exactly a majestic Pokemon, nor an Ice-type or legendary, it still finds a place to call home among Chilling Reign's most popular cards.
If the rest of Oath of the Gatewatch is similarly complex and powerful, we will be looking at a very interesting Spring
You lose the X utility of the spell but it is minor when you can spam it
So while the card is always in the minds of Magic players for being very unplayable, it's also always in another part of their minds that the card may become playable one day
One of the best black tutors in years, and these, of course, will be played a lot