I think modern Japanese is LTR, but besides that - I believe the project you worked in the past solves an important problem.

Besides pluralization (and e.g. Arabic having 6 forms zero/one/two/few/many/other), turned out number internationalization and currency conversion are big next challenges the community wants to address next.

> create ICU compliant JSON.

I think this is an excellent idea. I have a feeling in the future we will need ICU v2.0, sort of, but unfortunately it's an extremely hard problem and the probability to fail is pretty high (looks like project fluent is not actively maintained anymore: https://github.com/projectfluent/fluent)