Yes! We've talked a bit about this paper when thinking about the structure of our data storage and processing. To me the path Twitter followed seems very reasonable, so it's encouraging to hear that it looks that way to someone who gets dirty with data on a daily basis.
As it stands now, we weren't planning on enforcing any schema requirements in Kraken, but it'd be interesting to experiment with a standardized event-data format if y'all were in favor of it. Our most recent pass at a schema[1] -- mostly for binary serialization, to save bits -- has an otherwise-untyped (String-String) map for the KV pairs of the data payload. We intended to use an additional, optional field to permit specifying a sub-schema to apply strong typing to incoming event data. (We plan on storing things with Avro, but it's easy enough to convert between it and JSONSchema.) Event subclasses would be more flexible but require custom processing for each class. I'd normally oppose a standard model (Google doesn't use one internally, for example) but as Twitter made it work, I think it's worth exploring.
Thoughts?
[1] https://www.mediawiki.org/wiki/Analytics/Kraken/Data_Formats#Event_Data_Sche...