To say Awakening wasn't a step up towards a lot more common anime tropes would be lying. Awakening is honestly the first Fire Emblem game to have such quantity discussion and talk over husbando/waifus. There's also the fact that certain characters do pander towards otaku (this is not to say anything about the quality of their characters. I do love the characters I'm implying) and previous Fire Emblem games never featured them in such a capacity. There's also the art style change (In no way am I saying this is bad either. It's just Kozaki's art is something you don't struggle to find a similar style of in the anime of today).
Besides @
Weeman
's points, It's also worth noting that shipping mechanics, and even a fair bit of pandering, are not altogether new to the series. Genealogy of the Holy War would be a solid example of another game where matchmaking was a key mechanical element, and many of the support conversations in at least the games I have played (7 and 13 specifically; 10 was an outlier) have romantic undertones with multiple characters, allowing for some degree of shipping according to player preference, which is in essence all that is being offered in Awakening.
In addition, a large number of Fire Emblem characters throughout the series can be characterized with common anime tropes; such tropes are mixed and matched frequently to create characters in all kinds of popular media, and Fire Emblem games require many characters as it is. It would honestly be unfair to single out Awakening in that regard. Compare Sain and Virion, Oliver and Excellus, Nephenee and Donnel; you can see some similarities. It would admittedly be more difficult for me to pin down analogues to Tharja and Nowi, though perhaps someone well-versed in more than three games could offer suggestions.
At the end of it, the primary factor in the increased interest in husbandos/waifus likely comes down to the expanded fanbase and little more, as Awakening finally tapped into players who can play for story reasons rather than tactical gameplay reasons. In my opinion Casual Mode did more for such things than any part of Awakening's story or characters ever did.
So very close to the swankiest of Mii outfits, and yet so far.