Jiang Cheng does not qualify as the Jiang Sect Heir

What if each Sect had a tradition or spiritual test regarding inheriting the Sect leadership, and Jiang Cheng does not qualify or pass the test?  

This idea came from considering how different Jiang Fengmian is compared to Madam Yu, and how Madam Yu's personality causes such conflict within the Jiang Sect.  What if her introduction to the Sect through marriage to Jiang Fengmian caused certain aspects of the Jiang traditions to morph and influenced her son's behavior and spirit in such a way that he no longer represented the "Jiang" at all?  Instead, he is more of a Meishan Yu descendant than a Jiang descendant, despite his blood... if there was some sort of spiritual test to validate his position as Sect Heir, and his upbringing/influence by Madam Yu, actually tarnished his qualifications, what would happen?

Often, Madam Yu is characterized by her aggressive and paranoid behavior - stuck in the past regarding what she felt was a personal insult to her marriage and unable to move past it.  She cannot find joy or contentment in her life.  She seeks to criticize all of the Jiang traditions, particularly Jiang Fengmian himself, who she finds as weak and undeserving.  Well, who's to say that she isn't the one that is poisoning the Jiang Sect and causing its ruin?  Her loud and aggressive behavior makes it hard for the passive Jiang Fengmian to control, but there needs to be some boundary that she cannot overcome and has to submit to in society... otherwise, she (and all of Meishan Yu, assuming they are similar), would not be able to interact with the gentry and cultivation society.  Her martial sister, Madam Jin, seems more reasonable despite her own marital problems. 

So, what if each Sect had some sort of spiritual test or array that was a "rite of passage" to assign a person to the Sect Heir position.  Normally it is a male, but females could qualify if they best represented the Sect principles and spirit.  In the Jiang case, they did not even consider Jiang Yanli, and so she didn't go through with the test when she reached her majority.  Before Jiang Cheng is to go off to the Cloud Recesses lectures as the Sect Heir interacting with other Heirs, he must go through the rites.  

Let's say that he does not pass - we all know he does not embody or even seek the Jiang motto:  Attempt the impossible.  Instead, he is more likely to scoff at it and sulk when things don't go his way.  Perhaps Jiang Fengmian is nervous that his son won't pass and because Madam Yu does not truly understand what it means to be a Jiang, she doesn't allow him to try to "soften" her son or encourage him in other ways that aren't training.  She believes ruthless strength is the key, not an open mind and kind consideration of all perspectives.  How can you attempt the impossible if you don't even see potential in a less obvious path?   

Regarding Wei Wuxian, he could be a plot point, especially after Jiang Cheng fails.  Madam Yu might see Wei Wuxian as even a greater threat - did Jiang Fengmian think to replace her son with Wei Wuxian as heir?  She would want to hide the results and not let others know that her son failed.  She would refuse that anyone else go through the rite.  Once the rites pick an heir, that person cannot be replaced until they die or step down of their own free will.  It is a spiritual decision.  

If this is found out before the Cloud Recesses lectures, it would be a major gossip point... what will happen with the Jiang Sect?  Would Jiang Yanli now be considered?  What does it really take to be the Heir?  How does Jiang Cheng need to change and does he even want to?  I think there would be a lot of confusion and disruption around this.  Meanwhile, look at their Head Disciple - he has repeatedly done the impossible:  he made the Second Jade his friend, he created a new talisman, and embodies such a bright and brilliant spirit?  Should be the Heir instead?

I think a key point is that despite the gossip and rumors, Wei Wuxian does NOT want to be the Sect Heir.  He would refuse to participate in the rite, because he doesn't want to take that away from Jiang Cheng, but he also doesn't want to be the Sect Leader.  He wants to roam free and be a wandering cultivator like his parents.  Perhaps, he might even announce he wasn't even planning to stay long term with the Jiang Sect - that he wanted to leave to have more freedom to roam and help the people.  Perhaps Lan Zhan gives him the support and courage to finally vocalize this, as Lan Zhan would join him on the journey together. 

The more internal strife in the Jiang Sect and the leading clan could cause Wei Wuxian to abandon the disaster he sees coming all the faster.