when it is, its more often as a rider on an already powerful spell like Mirror Entity, Mutavault, or Crib Swap, not because its essential to keep a tribe together
The protection is odd and strong, basicallly none of the regualar instant and sorcery speed removal spells can target it, enchantments like O-rings can't target Emrakul, and haste creatures certainly can't damage it, so the main response to be concerned about is removal that doesn't target like a board wipe or edict
The one legendary creature from Oath of the Gatewatch that I really wanted to build around was Ayli, Eternal Pilgrim, and shes been out there in Magic-land for a while
You can also imprint Mystical Tutor to allow you to find Nexus of Fate each turn, giving you a chance to have infinite turns
Zenos yae Galvuss dragon flip mode is also fairly easy to pull off, as youll just need a Sephiroth's Intervention for its so-called friend. Seifer Almasy Rafiq-style double strike is a great start, but Seifer Almasy has plenty more to offer