I have an application where I want around 1 second of render delay. I am doing live caption, and I delay my video and audio by a second, but don't delay the captions. The result is the captions appear synced with the speaker, which is a very nice effect, rather than them being delayed. So of course I do this with two levels of 500ms render delay, and that works, but it's a kludge. Why not just allow the render delay filter to be as large as I want to set it. If you imagined people had no need for longer delays, that turns out to not be true.
It would also be nice if I could do audio delay in a filter, rather than in the audio advanced settings. I want to switch from scenes which have the audio delay to those that don't. Now, I can create different audio devices with different delay, but it is much better to mix in your delay later on in the stack, otherwise you have to build two versions of every underlying scene based on whether you want delay or not. Very frustrating. Renderdelay could offer an option to also delay audio, or there could be an audio delay filter and that would do the trick.