I don't play Neheb so I have no feelings there, but I am genuinely curious. Why is it okay to change the rules/wording and make a major functional errata to how Neheb works, but not make the nephilim and Godsire legendary in the name of avoiding functional errata? It's not like Companion where it was an emergency thing.

I know we’re looking into this issue.That said, there is a difference between changing a card and changing a rule which results in a card playing differently. The first is functional errata (we’re actively changing how the card works). The latter isn’t. We’re changing how the game works and the relevant cards play with the rules as they now exist. Here’s an example. Lifelink used to stack. If you had two copies of lifelink on a creature you gained twice the life. We then changed how lifelink worked. Every card with lifelink now worked differently, but that wasn’t us specifically redoing any card.

Why are cards that seem to work perfectly with the commander decks sometimes not placed in the decks? Godsire seemed a perfect fit in the token deck and the gitrog monster seemed perfect for last years land deck.

Two answers:1) There are a lot of cards that could be considered a “perfect fit”, and that designation can change player to player.2) Commander decks, like any product, have restrictions for the people designing them. What seems like an obvious inclusion might have not been possible for a whole host of reasons.

What was the first mythic rare that you ever designed?

Mythic rares I had a hand in the design from Shards of Alara, the first set with mythic rates: (note: “had a hand in” means that for many of these cards I was not the only one who was involved in the design) Godsire Hellkite Overlord Prince of Thralls Sedris the Traitor King Sharuum the Hegemon Sphinx Sovereign Tezzeret the Seeker