I disagree with your "too much ceremony" premise in general, but in particular I don't think it holds true for nom parsers. Here are two examples I've been working on:
https://github.com/djc/askama/blob/master/askama_derive/src/...
https://github.com/djc/tokio-imap/blob/master/src/parser.rs
If you look at the parsing logic that makes up most of those files, I don't think you can reasonably argue there is a lot of ceremony going on.