Some style manuals (but not this site) recommend that phrasal adjectives be hyphenated regardless of their position, and a few such expressions (such as far-reaching) are always hyphenated regardless of position or style authority.

What is more far-reaching?

If you describe actions, events, or changes as far-reaching, you mean that they have a very great influence and affect a great number of things. The economy is in danger of collapse unless far-reaching reforms are implemented. Synonyms: extensive, important, significant, sweeping More Synonyms of far-reaching.

How do you write far-reaching?

Far-reaching sentence example. John's activity indeed had far-reaching effects. I guess people don't realize the far-reaching aspects of cheating. His far-reaching hand even extended to Italy.