From a development standpoint there are a lot of things I prefer from the old Post Redirect Get workflow. The biggest thing I don't miss is modeling complex data in a form. SPAs let me sidestep this because it's JSON, which is much richer for modeling data than a plain form, going both ways. If form JSON (https://darobin.github.io/formic/specs/json/) was widespread I'd probably drop almost all my SPA usage immediately.