In talking to Shrey Banga recently about this, I learned that Quip has a similar process, except in addition to having an experienced engineer or tech lead on your team as a reviewer, they also suggest having an engineer on a different team review the doc.
A release plan should focus on the actual deadlines without specifying release details. It helps to maintain the existing documentation. While those are among the useful side effects, they are not the reason why we write design docs.
I promise this is different than your high school English class.
What are some negative consequences and side effects? Are you using software design documents when building new products? Write only exploratory code, make it a rule that none of it gets merged into master.