Hi A number of readers have made comments on this topic recently. We have created a document that does some analysis of common ML models and related APIs. We hope this can drive an approach that will result in an API, compatibility matrix and involvement from the same groups that are implementing transformation runners (spark, flink, etc). We welcome comments here or in the document itself.
https://docs.google.com/document/d/17cRZk_yqHm3C0fljivjN66MbLkeKS1yjo4PBECHb-xA/edit?usp=sharing