Answer: Each sign has a higher and lower vibration. One person can manifest the worst or best qualities of a sign. This depends on other factors in the horoscope. For one to be strongly connected to Spirit/God and sustain a long interest in spiritual matters it is important that he has a strong 9th house and its ruler. This is the house of God and moral. One also has to have more light in the horoscope than darkness, meaning the more spiritual planets should be stronger than the material ones: Jupiter, Sun and Moon are spiritual planets, if there are big afflictions to them, it will be hard for the person to keep on the good side, meaning to be highly moral, to have a personal connection with Spirit to lead a clean life. As you can imagine it is rare to see such horoscopes as most people in incarnation in these times, are quite imbalanced and have many issues to work on. An astrologer has to consider quite a few points in the horoscope to come to some conclusion if the person will be more spiritual or more worldly, the sign of the Sun is one of them, but it gives one piece of the puzzle only.
Sun in Leo is a very strong position as the Sun rules Leo. The Sun is a very spiritual planet--it signifies the centre, the core, Spirit, so you having a strong Sun in the horoscope is a very good indication for the manifestation of the Light in your life, but this by its self is not enough to determine in which group you will fall.This position of the Sun should bring a strong will and personal power--weather you use it for Material or Spiritual pursuits will be determined by other factors, like the house position of the Sun in your chart.