Hello Holy EPIC.
That is an interesting thought! The Myer-Briggs Personality is 16 personalities and based on your percentages on a 4 dichotomy scale of: 1. How you are energized, 2. How you enjoy gathering information in the world, 3. How you process and make decisions of the information you have perceived and lastly 4. How you structure your life based on the first 3.
You can usually receive a free Comprehensive Myer-Briggs Personality test via you school. They should offer it free if you pay student fees. Working for the SUNY system, I know they offer it for free.
I myself majored in Psychology and worked in Student Life centered and was heavily involved in helping students discover themselves using the Myer-Briggs as a tool.
Within the Myer-Briggs the Keirsey Temperament is used along with it to determine what kind of "temperament" you have which is a bit different than personality. (http://www.keirsey.com/4temps/overview_temperaments.asp) It's more of what emotional deposition you naturally have and that usually does not change. I'll explain why in a bit.
I myself am a X-NFJ (ENFJ&INFJ). I say X because I am right in the middle and my E and I flip-flops depending on which community/setting/environment I am in. (.ie: Friends vs. Work) So regardless whether my E or I flips, I am under the Temperament of "Idealist" which is determined by the middle two letters. And being an NF's tends to be supporting peoples. We are Ideal, and we make great teachers, counselors, healers and champion to people. We gravitate towards those roles and so, I gravitate towards the support role!
When I first played, I naturally picked Soraka and Sona and I loved playing support even though no one else liked playing it. It was something I loved to do and I was adamant in getting good at even though it was such a "high expectancy" role. Next was jungle and lastly Mid. I have not tried Top. I have tried ADC (Marksmen) and I am just not good at it. HA.
However, I would remark that I play the game holistically as myself. I bring my values and who I am into the game. However, Internet Psychology is a very tricky thing and personalities are not static with a person's personality IN REAL LIFE because of anonymity. They are able to be as TOXIC as they like and get away with it knowing there might not be real consequences besides a reform card that they may ignore, "chat privileges" or a ban. With a ban they make a smurf account. I do believe kids and players do bring this idea of anonymity "trolling" fun into their real world experiences. And in places that they can get away with things due to anonymity, they will take it because it has become second nature to them. (Example: http://www.helpmesave300.com/) Now I'm curious how many of those kids were League Players.
Also, Myer-Briggs only matter perhaps in a Pro-League Teams as they need to play with the same people and know the people irl. Myer-Briggs matters very little in how one can cooperate with another based on 1. Anonymity 2. Inconsistent, ever changing teams and social environment, or the lack thereof.
Myer-Briggs is designed to understand your strengths and weaknesses, to grow and to depend on each other. Being aware of this helps you know who to best work with based on your strengths on weakness so that you can GROW via complimentary partner/team and be the best YOU. Given, it is very hard for that to occur in MOBA games for the players like League.
But for myself, what does that mean as a LEAGUE PLAYER. Well, it makes me want to work for RiotGames as a Player Behavior Specialist. :)