I have to agree with this completely. In fact, I thought this was the intended behaviour of the "burst" argument, and it wasn't until further testing that I realised its true meaning.

I am looking for the exact same behaviour here – to allow *actual* burst requests before the delay starts to kick in. The eventual 503 is not necessary. I believe this is a very common scenario and it would likely benefit a lot of others looking for the same kind of thing.