Ruric Thar, the Unbowed absolutely chunks anyone foolish enough to cast a non-creature spell (including you, but thats the Gruul way)
A character with the Singer keyword counts as a set amount of Ink for playing a song, reducing the overall cost and freeing up more of your Ink to play new cards
For the moment, it seems as though Wizards of the Coast will remain conservative on their deployment - Rosewater said they want to see how players respond before hanging their collective hats on this shiny new card type.
However, if Everflowing Chalice has no charge counters on it, activating its last ability won't produce any mana
How long games last: 20 to 40 minutes per match, with a tournament usually running 3 to 4 rounds total
Izzet is for you if you enjoy passing the turn with all of your mana untapped, desperately waiting for an opponent to try and play the game only to be shut down by whatever interaction you have in your hand