Sadly and obviously the answer to that question was already addressed in their announcement that no cards from the Reserved List will be reprinted in this set BUT we already know not one but TWO of the all-stars that are going to be in the set
Tarkir: Dragonstorm Spoilers March 19 | New Surrak, Legendary Combo Enchantment and Jeskai Precon Tarkir: Dragonstorm Spoilers March 20 | New Zurgo, Mythic Reanimation Spell and Mardu Precon
You can then easily dump your infinite mana into your X spell or mana sink of choice (Comet Storm, Staff of Domination, etc.) to win the game or lock down the board
Sure, it's a little 1/1, but it's got reach, can produce any color of mana, and with a slight investment, it can trade with another creature in combat
I ended up giving it the ability to tap for every color but green (as the mana cost covered making the card green)