The MBTI has a way of correlating with the classical temperaments of Sanguine-Choleric-Phlegmatic-Melancholic from Galen's days. The system assigned Keirsey's behavior types of SP-SJ-NF-NT to different temperaments. Nostalgic SJ's were typed Melancholic, while SP's, with their strong desire for immediate pleasurable sensation, were Sanguine.
Originally the NF idealists were to be typed as Choleric. You see, the modern definition of Choleric generally means that the person is disciplined and in control of emotions, qualities of a hard worker and a good leader. However, this newer definition draws from different, later psychology. The original definition of Choleric ironically meant that the person was only more emotional, thereby expressing more anger and also showing more determination when pursuing what they really believe in. The implication was that these people were more passionate and would always prove more productive than those who suffered less, which is less true in this modern world. Hence, they would be NF, leaving Phlegmatic for NT, the last Keirsey Temperament left.
However, the temperaments were later switched between NF and NT because although the NT's were more "cool-headed," they were also known for being the more determined, and apparently these were now the defining traits of the Choleric, not extroverted neuroticism as it had been before.
However, this raises several issues. Firstly, even while still using the old Keirsey system, the NT Rationals, though certainly determined, would fall under the umbrella of "Choleric," but less so than the SJs. This is most apparent comparing the ESTJ and ENTJ. The original definition of "Melancholic" meant the introverted analog to the Choleric, and it also meant that these individuals would be the types most suited to deep cerebral thinking and calculation, while the extroverted Cholerics would focus more on putting these plans into action.
Though intelligent individuals have been found among all types, generally ENTJ scores for IQ are higher than ESTJ, and NTs over all typed as the most intelligent.
In addition, the ESTJ has a slightly harder time holding back anger than the ENTJ. When comparing Melancholic and Choleric, the Choleric would still show more anger than the Melancholic because of extroversion of anger, so in this case it would be more correct to type the ESTJ as Pure Choleric and the ENTJ as Choleric-Melancholic instead of the other way around. This would make NT's in general Melancholic and SJ's Choleric.
However, there is still issue with this system even with these changes. SJ and SP both indicate a single cognitive function, Se for SP's and Si for SJ's. NT and NF, though, both indicate two cognitive functions, saying nothing of their positions in Introversion/Extroversion. In addition, it pairs all people who are Intuitive and Feeling as one collective umbrella of a type, to say nothing of all those who are Sensitive and Feeling. It does the same thing with the SP's, pigeonholing all people who are Sensitive and Perceptive without comparing them to Intuitive Perceivers.
This unequal classification glazes over important similarities between similar types, e.g. ESFP vs ENFP, and in doing so assigns certain qualities and even archetypes to temperaments without considering how the individual letters would affect each type. For instance, ENFPs are Idealist NFs, known according to Keirsey for being most concerned with humanity and their ideals. They are one letter apart from ESFPs. Both types are E, F, and P. They are both extroverted and they both have Fi auxiliary, so they would behave certain ways. However, ESFPs are SP Artisans because they have strong Se, which would give them focus on concrete sensory information in the physical world. They would be pegged as the ultimate "thrill seekers," which they for the most part are.
However, these archetypes are very different from one another even though the cognitive function orders are almost the same. Ordinarily, ESFPs and ENFPs would easily sympathize with others in their environment, and as they matured, take greater and greater consideration for those around them. They don't have Fe, so they aren't "in the moment" as to how other people are feeling, but assuming both individuals are healthy, they would both show the same amount of concern according to their cognitive functions because the only difference is their primary Pe, the different ways in which they perceive reality.
The ENFPs, being NF, are portrayed as the idealists that they generally are with a deep concern for others. This is true in healthy individuals. However, the assignment of these altruistic characteristics to the overall NF creates an idealization of anyone with these two letters and can often lead to the Forer Effect. ENFPs are idealists because they deal in people (Fi) and ideas (Ne.)
That said, according to the nature of Fi ESFPs should behave the same way, yet other types frequently call them out for being rude or inconsiderate. This, coupled with the association of all SPs collectively with "thrill-seekers," creates the impression that they are no longer like their ENFP cousins in how they care for others. This is not true. Both types have Fi auxiliary, so healthy individuals would care about other people to the same degree: the ESFP simply absorbs reality in a different way, but the motivations are exactly the same.
This association of different traits with such subjectively selected traits gives the final impression that SPs are careless, SJs are controlling and dogmatic, NFs are caring and deep, and NTs are emotionally controlled and logical. While that may be true, in terms of cognitive functions this is simply not a fair way to classify. J/P let you see the flaws of SPs and SJs, while F/T highlighted the advantages of NF and NT. NJs can be in fact just as controlling as SJs, and NPs, with their emphasis on whole new ideas to explore around them instead of just sensory stimulus, are probably even more careless than SPs.