Bahasa Indonesia the sole language of ASEAN? No way!

If Bahasa Indonesia is set to become the sole working language of ASEAN, I’ll oppose it. It’d be much better, I believe, if every national language of ASEAN members, excluding English, is recognised as the official working languages. Wouldn’t it be cool to see the youth speak their mother tongue + 1 ASEAN member’s national language? (Filipino and Vietnamese are on my top list)