It's not just defining, it's also how much that color is played in the top 50 cards. Blue, as of my original rant on this a week ago, had 2x the cards that White did( 6 blue to White's 3). Anafenza never really defined modern in the way that Cruise/Dig did.
Cruise had burn players splashing blue because "Hey, I get to draw 3". Swiftspear has solidified itself in Burn and was part of what makes Kamikazoo work. Collected Company made Podless Pod an actual deck, allowed for Elves to exist as a deck, gave us a semi-viable Slivers/Ally deck, etc. Kalitas seems to have become the top end for BGx(The stable rock of the format), as he's basically edged out Chandra, Huntmaster, Tasigur, and Pia and Kiran Nalaar. He's also been seeing play in Mardu/Grixis/Abzan. Kalitas is lifegain+Gravehate+ Token Generation+ a clock.
So yes, I'm sorry that I don't view Anafenza Kin-Tree Spirit, a card that is used in one deck as a backup Melira, as on par with a card that had people splash to play it, a card that has become a staple in one of the aggressive decks in the format that is always tier 1, a card that enabled so many archetypes that previously weren't consistant, and a card that is basically everything Black could want out of a 4 mana creature.