I'm the author of the post and the lead on this project. Many of the costs you mention aren't so bad. As mentioned earlier, we actually consider learning GH and Markdown a plus for non-devs. As for comments and writing Python, some pain here, but were ultimately solvable.

Performance also wasn't the only plus here. Closing major security holes, making more of our content and technology more open, and moving to a platform that our devs liked working in are just some of the other wins.

It's too early to say definitively now, but we think the change is probably a good one.