First time I've heard of KIP-932 and it looks very good. The two biggest issues IMO are finding a good Kafka client in the language you need (even for ruby this is a challenge) and easy at-least-once workers.

You can over partition and make at-least-once workers happen (if you have a good Kafka client), or you use an http gateway and give up safe at-least-once. Hopefully this will make it easier to build an at-least-once style gateway that's easier to work with across a variety of languages. I know many have tried in the past but not dropping messages is hard to do right.