It's not hard to make a case against gettext, despite its maturity and large ecosystem.
IMHO pluralization is a prime example, with an API that only cleanly handles the English case, requires the developer to be aware of translation gotchas, and honnestly confusing documentation and format. Compare that to MessageFormat's pluralization example (https://github.com/unicode-org/message-format-wg/blob/main/s...) which is very easy to understand and fully in the translator's hands.
IMHO pluralization is a prime example, with an API that only cleanly handles the English case, requires the developer to be aware of translation gotchas, and honnestly confusing documentation and format. Compare that to MessageFormat's pluralization example (https://github.com/unicode-org/message-format-wg/blob/main/s...) which is very easy to understand and fully in the translator's hands.