It would make since actually. Not only has he always wanted to be Hokage, but it would be similar to the Kakashi-Naruto Hokage scenario. Kakashi became Hokage until Naruto was old enough to take it for himself (not to mention the Sensei-student trope of Hokage) so it would actually make sense if the official 8th Hokage is Konohamaru and then Sarada becomes the next