At one point (when I first tried this) I'm pretty sure youtube didn't have a link to an rss feed in the source. I had grown used to going to source and searching for "rss" and "xml." However, I just checked and they definitely do have a link now!
But on a first glance, it seems like alternate links for channels are back, but playlists are missing. Still, that might be a step forward.
Using openrss.org as an intermediary might work as well, but not ideal to rely on a third party for that.