@ysandersTreason What is so perfect about that? She is an adult working at a cabaret club while Rei is still a high school kid that isn't even allowed to drink alcohol. It is really mismatched. In Japanese law, Rei is under 20 and is still a minor. When they stand next to each other, Akari looks old enough to be Rei's mother and Rei actually views her as a mother-figure.
Rei and Hina feels more natural. Most Asians prefer the wife younger than the husband since it is our tradition. The author aldready put Rei with Hina so there is no use wishing for something different.