I get what you mean. Before Azure Summoning was around, flying decks weren’t really a thing, so there would be reason to believe it’s the card to target since flying decks became stronger only after its release.
That said, just because a card came last, doesn’t mean it’s the offender. There are plenty of cards that had been around for ages that had to be changed to keep new cards in check or allow archetypes to grow. Old Shadow Creep would be broken in a game with cards like Sphere of Darkness and Ooz. The change to Flash Reincarnation keeps monsters like Juggernaught and Kraigon in line. Old Mana Vortex (back when it cycled) couldn’t exist in the same game as Firestrorm Mantra. That’s just to name a few.
I’ll ask something else then. Let’s say I don’t swap any cards in the combo. And let’s say I play Azure Summoning, and play a Dragonlark first because it’s my only flier. Then I draw the 2nd Dragonlark. And then the 3rd, and only afterwards do I draw my 3 Skywings. It’s suddenly a 9-mana play. Is it broken as a 9-mana play?
I honestly think there are much stronger plays at that stage of the game, and some decks can have you beat before you even reach that point. That’s why my problem is with Skywing. The combo is only oppressive early in the game when your opponent doesn’t have the mana to answer it. At later stages of the game, it’s no stronger than any other lategame card or combo.

