Once a problem becomes a non-toy problem, pipelines lose. troff(1) will do all the hyphenation (C or C++ code) in your code. Ironically troff is like TeX, it processes documents.

Of course troff hyphenates. Its job in the pipeline is to hyphenate, compute layouts, and output input for dpost. If your argument is that decoupling hyphenation from layout is difficult, I believe you are wrong. Splitting the hyphenator into a separate program is straightforward enough. Consider the text formatter

  hyphen < input | layout | topostscript

where hyphen inserts all possible hyphens, and layout discards those which are unnecessary.