what is better for ASEAN in the future ?if all countries in ASEAN united ?

The Association of Southeast Asian Nations,^[3] commonly abbreviated ASEAN ( /ˈɑːsi.ɑːn/ ah-see-ahn,^[4] rarely /ˈɑːzi.ɑːn/ ah-zee-ahn),^[5][6] is a geo-political and economic organization of ten countries located in Southeast Asia, which was formed on 8 August 1967 by Indonesia, Malaysia, the Philippines, Singapore and Thailand.^[7] Since then, membership has expanded to include Brunei, Burma (Myanmar), Cambodia, Laos, and Vietnam. Its aims include the acceleration of economic growth, social progress, cultural development among its members, the protection of the peace and stability of the region, and to provide opportunities for member countries to discuss differences peacefully.^[8]
ASEAN covers an area of 4.46 million km², 3% of the total land area of Earth, with a population of approximately 600 million people, 8.8% of the world population. In 2010, its combined nominal GDP had grown to US$1.8 trillion.^[9] If ASEAN was a single entity, it would rank as the ninth largest economy in the world.