I believe the “missing” is something we didn’t get to yet for the terms aggregation. We do plan to support it. What is the “Other” you’re referring to?
What is the error you’re seeing for rollover?
We do treat it as a somewhat special index, but it is just an index. The only thing we do extra is add a setting that specifies it contains rolled up data so we can intercept search requests to the index and transform them. The reason we do this is because the data in your original source index and the data in the rolled up index are stored in different formats. i.e. you might have
"some_number": <number> in a bunch of your original documents, but when you do max, min, sum, avg, etc. on that field we need to store a bunch of different values.
We wanted to allow users to query the original and rolled up index with the same queries though, so what we do is intercept search requests and transform them to match the new format.