Lesse... There was an ethnic riot in the east (Maluku and Poso), and in Kalimantan due to ethnic tension between transmigrant and native. I think almost everyone knows what happens in Java at the time. The active separatist movements are in Aceh, Papua, South Molucca, and Timor (remember Indonesia hadn't pulled out yet)
So total disintegration of Indonesian state wasn't plausible. New Order really build up those nationalism. Separation East Timor (OTL), Aceh (unlikely), and Papua (really unlikely) however, was possible.
The only way for balkanization, therefore, is via political split, which I don't know whether it is possible or not