It might be. Popularity in the fanfiction world depends on various factors. If it manages to capture the essence of the original source material while presenting Kuroko as a genius in an interesting way, it could gain a following. For example, if it delves deep into Kuroko's unique abilities and how they make him a genius in the context of the story, it may attract readers.
Perhaps it will focus on Kuroko's extraordinary intelligence being applied to solve various problems. Maybe he uses his genius to outwit opponents in a game or come up with unique strategies.
In such a fanfiction, perhaps it could start with Kuroko being targeted by a rival team who want to disrupt Seirin's plays. They might kidnap him on his way home from practice. His teammates would then start a frantic search, led by Kagami. They would scour the city, following any leads they could find. In the end, they manage to rescue Kuroko and their bond becomes even stronger through this ordeal.
A possible plot for a Female Kuroko x Akashi fanfiction could be set in an alternate universe where there are no gender - based restrictions in basketball teams. Female Kuroko joins Rakuzan instead of Seirin. Akashi, as the captain, is initially skeptical but soon realizes her potential. They start training together intensively. As they do so, they begin to develop feelings for each other. However, they face opposition from some of the team members who are not used to the idea of their captain being involved with a female teammate. But through their strong bond and love for basketball, they overcome these obstacles and their relationship blossoms.
One great Akashi x Kuroko fanfiction is 'The Red and the Blue'. It beautifully delves into their relationship, showing how Akashi's dominant personality and Kuroko's calm nature complement each other. The author does an excellent job of portraying their emotions in a Yaoi context.
The kidnappers could be motivated by jealousy. They might see Kuroko's skills and his importance to Seirin and want to take him out of the picture so their own team can have an advantage. For example, a rival team that has been losing to Seirin might think that without Kuroko, Seirin will be easier to defeat.
One common theme is the exploration of their complex relationship. Given their different personalities and playing styles on the court, fanfictions often delve into how they understand and support each other off the court. For example, how Akashi's strict and calculating nature might be softened by Kuroko's quiet and observant presence.
A new player on an opposing team could be the cause. This new player might be overly cocky and disrespectful towards Kuroko during a game. They could constantly taunt him about his lack of presence, which finally gets on Kuroko's nerves and makes him mad.
In the fanfiction, it might be someone from his own team. Maybe there's a new member who is insecure and feels that Kuroko is getting too much attention. So, in a fit of jealousy, this person does something that causes Kuroko to get hurt, like tampering with his equipment.