What factors of the Shari'ah that lead to Diversity

1. The classification of Hadith - transmission and preponderance
2. The linguistic understanding of the words of the Qur'an
3. Local custom
4. Cases judged on their own individual merits
5. Ijtihad - Individual scholarly reasoning
6. Public interest - this could change over time and may be applied narrowly in one region or country
7. Juristic preference 
8. Principle of Necessity - could become the norm until the necessity is over