Personally I'd go with the original proposal and limit ASN per
organisation. I'd also like to solve 16b ASN shortage by limiting
single 16b ASN to organisation who has downstream public ASNs (because
communities are important for downstream to signal information to
upstream).
Just for my understanding, is there any demand for 16b ASN from the community?
By default you get 32b ASN unless there is compelling reason for 16b. IANA gave the last block last year to all RIRs so if the requirement is there then it should be single 16b ASN to new LIR and nothing to existing ones. I believe only handful 16b ASNs are left in each RIR (though NCC may clarify)