Todd from the Apache Kudu (incubating) team here. I'll check this thread throughout the day in case there are any questions (and try to check the original post for comments as well).
Of course this is a huge optimization for data warehousing applications, where two co-partitioned tables can be joined without any network data transfer, and in some cases could even use merge join instead of hash based strategies. But, it's the usual time/scope/quality trinity, and we'd rather not compromise the third element.