Thanks! I'm writing a blog post now about how I got the majority of bash-completion running, so I'm now using OSH myself. This is the biggest milestone in a long time!

It exposed the slowness issue though. I have a plan for that, but it's a bunch of work.

It will help me if people try it and give feedback -- I'll give details in the post.

I definitely agree about Python 2/3. I think you basically can't overestimate the amount of inertia a popular language has. I'm sure there will be patches floating around for Python 2 for a long time after the core team stops maintaining it next year.

Another example is all the compile-to-JS languages. I think TypeScript is the most popular in part because its transition path is the easiest, i.e. it's a superset of JS.