"on what wings dare he aspire" refers to the tiger's appearance to a human. It delves into romanticism on the intellectual level. Respectively, it isn't an animal, but it is the thoughts about animals. Its about a hunter's ambition to kill rather than capture an animal (the tiger).  The person responsible for Red John murders is interested in killing rather than capturing humans.  He seems to be thinking he is above everybody.  A sheriff may get excited about being powerful, but it seems awkward.  Police don't remind of someone that thinks they are better than others.  However, some police use power to get what they want.  My top choices for who is into creating the Blake Association is a psychiatrist or police officer.  These two occupations are interested in helping society.  In fact law enforcement captures people, so Tiger, Tiger seems separate from police work - which takes my suspicion to psychiatrist.  He is busy helping people with their problems, but he doesn't work on his own.  He is selfless to the point that he needs to be considered a hero.  However, there is no "pat" on his back.  Wagner was helping children in Africa, there was never any personal time for him.  He knows he is depraved, so he finds some comfortable way to set himself up in prison (on deathrow).  Any admission of guilt is just covered by the fact that he has killed, and he framed Red John.  
Distant [deeps] refers to depth of one's spirit, and skies refers to heights of spirituality. Distant [deeps] is referring to the depravity reflected on by a hunter - who is hunting (rather than capturing). People find depth to be desirable in a person, because it resembles morals. The more pain you can feel the more human you are.  its as if "deeps" is feeling more human (than human).  Adding "distant" to "deeps"  makes a stark contrast to feeling human.  Red John is a person that is aware of the immorality of his killing.  He has values, but they are "distant deeps".  Red John could have killed Jane, but he probably wants to get caught.  His morality is catching up with him.  Jane's story is appealing, even to Red John.  
"Dare frame thy fearful symmetry" is the hunter communicating to himself, while hunting.  It speaks to the mind processing the fact that the hunter is a killer, and the hunt is for sport.  Basically, killing (instead of capturing) the tiger is victory, and the hunter is keeping himself involved.   Blake makes reference to the morality one deals with, when mentioning that the same creator of the lamb made thee.  The hunter thinks about letting the tiger live, but he decides to continue the hunt.  This is a deep character, I find it perplexing.  Mcallister seems easy to read.  A psychiatrist is much more complex; they have walls that they build to separate themselves from feeling - developed through years of attempting to be purely scientific.  A psychiatrist must relate to patients, and maintain objectivity - as professionals.  Wagner rather be remembered as a doctor that helped people - thats why he told Jane the reason he stole the money.  Any serial killer wants to be caught, and Wagner is no different.  Red John wants to surrender; its his humanity.  Wagner got caught, and he can continue to kill.  He can be let out, because he is friends with police.  He can run the prison from inside.  Jane is not likely to be able to get to him, while he is on death row.