The other inclusion, and why I run it over Sigil of the Empty Throne is that it is an outstanding mana dump for excess white mana
Unlike the other two cards, however, Kykar also works well as the head of a deck with Spirit creatures or other ways to make Spirit tokens, as Kykars ability to trade Spirits for red mana isnt strictly limited to the tokens it creates
Admittedly, this Doctor is a bit odd, though
The three cost instant redirects all targets from one spell or ability too, don't forget that last part
Witherbloom Apprentice As I mentioned earlier, this card with Chain of Smog gives you a 2-card instant kill combo in Legacy, which naturally makes this a desirable card
Sanjis brand new Leader card is here