Here’s the rules text:
Kefnet the Careful
Legendary Creature – God
Kefnet the Careful can’t attack or block unless you have seven or more cards in hand.
3u: Draw a card. Then, you may return a land you control to its owner’s hand.
What I think
I don’t think that Kefnet is a particularly good commander but I think this bird god is dope in the 99. Literally any deck that has midrange elements or can create a lot of mana can use this card as a mana sink for decent card advantage. When you have 7 or more cards in hand the God also serves as a indestructible blocker versus aggro decks.
The fact that its also a creature makes it super playable in decks like Momir Vig, Simic Visionary where searching for creatures is super easy.
The second half of the card draw ability is quietly super versatile – you MAY return a land you control to its owner’s hand. This is pure gas. You can reset glacial chasm. You can replay any land that has enter-the-battlefield value. You can activate the ability in response to someone using Strip Mine against you and pick up the targeted land. I have a decent Child of Alara Lands deck where this card is going to be great for long term value. You could also use cards like heartstone or training grounds to reduce the cost of his ability and draw more cards.
I think the best part about this card is that it is a long-term value option. If you are playing a midrange/controlling blue deck you can do nothing and hold up your shields (counterspells, interaction, etc) and if your opponents don’t pressure you you get to draw a card or two. This pressures your opponents to eventually confront you before you draw a bunch of cards and become incredibly difficult to kill.
I think this god could be an OK commander in slower games, I just think that he is better served in decks that include more colors. Either way I can’t wait to try him out!