Here is a visualization of how the issuers should be divided up in my opinion. Issuers that are labeled as not yet added I will be making requests for in the coming days. Upper and Lower Jambi have been requested for a few weeks with no action so far, so once they can be gotten around to they can be factored in. Issuers in italics are already in the proper location, and are just included to show the full scope of the proposed catalog
Maritime Southeast Asia
----- Islamic Sultanates
---------- Sultanate of Johor
---------- Sultanate of Kedah
---------- Sultanate of Kelantan
---------- Sultanate of Malacca
---------- Sultanate of Pahang
---------- Sultanate of Patani
---------- Sultanate of Perak
---------- Sultanate of Selangor
---------- Kingdom of Perlis
---------- Sultanate of Trengganu
---------- Sultanate of Aceh
---------- Sultanate of Banten
---------- Sultanate of Batubara
---------- Sultanate of Bone
---------- Sultanate of Demak
---------- Sultanate of Gowa
---------- Sultanate of Indragiri
---------- Sultanate of Palembang
---------- Sultanate of Pontianak
---------- Sultanate of Samudra-Pasai
---------- Sultanate of Siak
---------- Sultanate of Sumenep
---------- Sultanate of Deli
---------- Sultanate of Sulu
---------- Sultanate of Sintang (Yet to be added to Numista)
---------- Sultanate of Tidung (Yet to be added to Numista)
---------- Sultanate of Jambi
--------------- Sultanate of Jambi
--------------- Upper Jambi (Hulu) (Pending creation to Numista, must be added by mods)
--------------- Lower Jambi (Hilir) (Pending creation to Numista, must be added by mods)
----- Indianized Kingdoms
---------- Srivijaya
---------- Java (Including ONLY native coinage)
---------- Melayu Kingdom
---------- Kingdom of Ma-Yi (Must be added to Numista)
---------- Kingdom of Kalah (Must be added to Numista)
----- Uncertain Maritime Southeast Asia (Current issuer “Maritime Southeast Asia” should have its name changed to reflect the unknown attributions of the coins it contains)
----- Chinese Communities
---------- Bangka Island
---------- Kongsi Federation
Indonesia
----- Indonesian States
---------- Riau
---------- Irian Jaya
---------- Netherlands East Indies
---------------- Netherlands East Indies
----------------- Dutch New Guinea
---------------- Dutch Java (For the colonial issues in Java, which must be separated from the native coinage)
British East Indies
----- British Singapore
----- Penang
----- Sumatra
----- State of Maluka
This set up mirrors the setup of Zeno, as @Coinwalla mentioned before. The histories, peoples, and coinage of the Indonesian, Malaysian, and one Filipino Islamic Sultanates were very intertwined, making their separation within the catalog unhelpful. This suggestion helps keep the Islamic States together, differentiates between the Indianized Kingdoms, and the issuer we currently use as a repository for uncertain types. This setup also mirrors the current set up of the issuer “Central Asia” (which I ref for), and is set up in the most straightforward way for both collectors of the types as well as Numista users who are new to the coinage of the region to understand. I would hope this proposed set up for Maritime Southeast Asia would be more straightforward and easier to understand as well.
I would also like to ping @by.abay. As the current ref for pre-modern Southeast Asian, their input would be very valuable, and their agreement with this move would be 100% necessary for this to proceed.