I think all of these are good. Nadu especially. Didn't see Extortionist coming but that is also probably a good idea.
They hit more fast mana artifacts, which are going to continue to be a problem for EDH as they continue to print more powerful cards. I thought the comment about Sol Ring was interesting:
We should also talk about the elephant in the room. We're not banning Sol Ring and have no desire to. Yes, based on the criteria we've talked about here, it would be banned. Sol Ring is the iconic card of the format, and it's sufficiently tied to the identity of the format that it defies the laws of physics in a way that no other card does. Banning Sol Ring would be fundamentally changing the identity of the format. We aren't trying to eliminate all explosive starts—it happening every once in a while is exciting—and removing the other three cards geometrically reduces the number of hands capable of substantial above-curve mana generation in the first few turns.
I think they're doing things right here.