I'm glad to hear you would have found it beneficial!
I've definitely seen the same patterns at companies (and even introduced similar patterns).
The proposal linking was inspired both by IETF RFCs and by Jira issues. I love how both systems provide semantic meanings to such links (X obsoletes Y).
I do hope to marry the engineering love of markdown with management's love of WYSIWYG. Currently the proposal editing process is done via a syntax-highlighted markdown editor but in the future I'll add a WYSIWYG editor, then let users select a default mode.
To be honest (and I'm just some rando so feel free to ignore me), if you have an MVP I'd say forget about development and sell what you have. You're already better than what I've seen in industry. If anything, being able to take an existing decision database and onboard it to RFC Hub (even if done manually) would be a better sell than WYSIWYG to enterprise customers.