Regardless of the ideological differences, we need to really think about how sectarianism has been the strongest driving force behind the chaos in the Arab world. When somebody proclaims religious legitimacy, 'my Islam is more Islamic than yours', it creates animosity, and inevitably fuels conflicts. Islam teaches its adherents to study everything on Earth and in the heavens, and it's up to individual decisions to choose what he/she believes in, but I've never seen scripture giving you, any student of Islam, the right to declare other Muslims as heathens or apostates.
If you're feeling nostalgic, remember how Islam reached its golden age by embracing rich cultural heterogeneity and pursuit of scientific endeavors. Ibn Sina, the father of modern medicine, al-Khawarizmi, who wrote the foundations of algebra -- they may not be household names but they really should be. At least they should be household names for Muslim families from Nigeria to Indonesia
What the (Muslim) world needs is more unity in diversity, nation building, and economic, social and scientific pursuits -- and less bickering over tribalism and minor differences in the way we look, speak, and pray.