The proposal never made sense. Most people don't use desktop feed readers and even if they did this solution wouldn't be scalable (as Cadenhead mentioned). Google Reader knows when you update your feed because you already ping Google. In my experience they are grabbing the feed in a few seconds anyway--it's up to them to show this to users in real time if they want to but there is nothing stopping them.
It seems like Dave wants to continue using his out dated desktop software (the OPML Editor) to view feeds in a manner much better suited for a hosted product. That might be great for him, but I'd rather not change publishing on the internet so his decades old software can keep pace with Google Reader.
The proposal has the potential to support pooling of multiple feeds. For example, you can get the updates of thousands of feeds in one request. That saves a lot of bandwidth and processing time. Does that make sense?
It seems like Dave wants to continue using his out dated desktop software (the OPML Editor) to view feeds in a manner much better suited for a hosted product. That might be great for him, but I'd rather not change publishing on the internet so his decades old software can keep pace with Google Reader.