If you rewrite your app you end up with something better, in any language. It's an uncontrolled experiment, and so the headline is very likely misleading - this isn't about Python and Lua. And many of us have been majorly inconvenienced when a manager read a similar headline and declared that we would rewrite our app in language y, regardless of whether that language is appropriate to our circumstances.
Something like http://roscidus.com/blog/blog/2013/06/09/choosing-a-python-r... where the author actually considers multiple candidates and performs a controlled comparison would be far more valuable. Given that the goals sound very similar I'd be very interested to see a comparison between Lua and OCaml.
> If you rewrite your app you end up with something better, in any language.
You end up with something that is superficially better, but misses a lot of edge cases that the ugly legacy application covered. Fortunately, you have usually moved on to save other projects, leaving lowly maintenance developers to fix the problems, thereby creating job security. It's a win win situation, really.
Working code is worth a lot. No amount of unit tests will make up for the real user testing done in the wild. I have had some horrendous pieces of code that I kept because I knew they worked.
Something like http://roscidus.com/blog/blog/2013/06/09/choosing-a-python-r... where the author actually considers multiple candidates and performs a controlled comparison would be far more valuable. Given that the goals sound very similar I'd be very interested to see a comparison between Lua and OCaml.