Emphasis: giving a unified face to Aikido.
note: now only if they could unite the above.
Why do you think the aikikai should or could unite other styles?
Shodokan, Yoseikan, Yoshinkan, Shin shin toitsu aikido and Iwama shin shin shurenkai all had reasons to leave the aikikai an build up an own organisation:
Tomiki wanted to integrate aikido and judo and allowed competition. There are world championships. A lot of scholars all over the world: A style on its own.
Mochizuki wanted to integrate some other budo and aikido. In France its affiliated to aikido. But it is a style on its own.
Shioda wanted to continue the aiki budo of the postwar years. He explicitly didn't want to practice the aikido which is practiced in the aikikai. He called himself 'founder' and set up an own iemoto line.
Same with Tohei: He wanted to integrate Shin shin toitsu do to aikido. (He didn't only emphasize on ki.) And he has a follower, like Shioda had and Ueshiba himself had.
And Iwama shin shin shurenkai: I just read an interview in which Saito Hitohiro said, that at the Aikikai hombu dojo there is no real aikido.
So why do you think the aikikai should or could unite those differing styles?
The aikikai isn't responsible or in charge of other styles of Aikido. They are independent, autonomous and free. Don't they walk their way in their own right?
And on the other hand: The aikikai intentionally didn't want to integrate those aspects into it's aikido. That's why ther was a parting of the ways.