If you are doing date range partitioning it should be fairly simple to load data into the latest table directly. That was the way I originally intended for it to be used. The rules approach isn't something I'd recommend as a bulk loading option and its a lot more complex anyway.
The problem we have with blindly loading all data into the latest table is that some data (< 5%, possibly even much less) is actually delivered "late" and belongs in earlier partitions. So we still needed the ability to send data to an arbitrary partition.
