As someone who is a heavy user of RSS feeds (check my cryptography RSS feed[1]) and has had to implement RSS feeds for my websites:
1. we need to move away from XML. JSON would be a much better modern candidate.
2. we need better support in all web-first programming languages, and possibly in web frameworks.
3. we need to have a stricter set of rules on how to use HTML5 tags like articles, sections, and such. An RSS feed shouldn't have to be manually produced when a crawler should recognize modern HTML5 tag and produce one on its own.