Yeah, having those extra years to grow up in really helped her hone her own (awesome) personality, for which the 48 franchise is much more accomodating of, anyways. She wouldn't have been our beloved safe and peaceful pervert otaku in MM, as can be seen simply in the way she euphemized her love for manga/anime and idols with "music and art."
It's because she was older when she auditioned for SKE that she was so self-assured and such a smooth talker, as well as becoming somewhat of a nurturing character in KII with how much her team members praise her.
Not to mention the way she's so set in her quirky persona, just completely shameless with a tinge of cynicism that only comes with age, works excellently not just for herself, but as a foil for the other members who haven't fully developed their characters yet and need someone else to play off of. If she had gotten into MM, there would already be several senior members taking that role, with most of them needing to graduate before Airi would be able transition in that direction, and in the meantime she might develop in a completely different direction and role. Given her stating her lack of academic prowess, I'm thinking she might have gone in the witty boke direction a la Kamei.
Also, what would we do without all of the Renairin.
One could imagine a stronger RenaManatsu ship, but then again, it feels like Rena's friendship with Airi is partially responsible for Rena now being so shameless fangirling over members.
The direction of HapiHori would be drastically different as well. Nishishi and KanaKana still would have their Team S friendships, but HapiHori's signature banter is very dependent on the specific dynamic between the three, from the focus on otaku interests, to perving on the lolis, to all of the talking about SGayE. It's really Airi's image as a proud otaku and pervert that opens the door to making these topics commonly available, as otherwise they'd probably be restricted to safer and more boring idol talk topics.
But it's interesting to think about what could have been.
Would she have bonded with Aichan over video games, or would she have skeeved out Leader over the dating sims?
Would she have had dork-out fests with Linlin?
Would she have fangirled/perved over the members, becoming the new Sayu?
What would an Airin-Aichan duet be like?
If she had been the lone 7th gen, what would have been made instead of Rainbow Pink? Would she have been pushed as a new ace anyways? (Would Tsunku have written a rock song for her vocal talents?) Would she have done Kirarin Revolution, and how would that change the series, given her interest in the industry? (Plus, now we know she has the seiyuu skills from AKB0048)
If she had joined with Koharu, would Koharu have been so lonely, or would she have been more insecure about her vocals?
Airi in Iroppoi Jirettai.
Airi in Egao Yes Nude.
Airi in Kanashimi Twilight.
Airi being wasted in Haromoni@
Would Sayu and Gaki tsukkomi her otaku lifestyle?
Would the 9/10kis fangirl over her, assuming she had developed her boyish nature by then?
The inevitable WAiri H!P concert shuffle unit.
(Maybe she would have been in Aa! instead of Akari
)
Airi with MM at Anime Expo in 2009.
(Also
she would otaku-fangirl so much there.)