CORNBRINGER
If he truly becomes the dark avatar it will truly interesting because no other fanfic had this idea i think
please become a dark avatar,using his empath he can make vaatu feel love,joy and all other emotions and tame him from within, not to mention being reborn in avatar korra wouldn't be so bad,but since vaatu is raavas opposite he wouldn't be another soul but himself rather than a new life, memories and all,unlike raava and the avatar.
I'd say go for it. While Akira isn't really evil per say- He's an ideal host for Vaatu; with his status as an outsider. Chaos is necessary for change- and Akira can guide that chaos as a host. Vaatu is pretty much immortal... So killing him isn't really an option. Becoming host to Vaatu let's him essentially become the warden. A warden to a prison of Vaatu's own making. Plus energy bending with modern knowledge offers a unique perspective.