But it's very easy to go way overboard with this. Many writers spend as much or more time seeking excuses to avoid writing, because writing is hard. It's an inclination perfectly skewered by Merlin Mann's parody of distraction-free writing environments (via forkbombr via DF):
While some so-called environments that are less free of distraction may display one, three, or even more lines of text—all at the same time—we understand that if you could only achieve the theoretical removal of all theoretical distractions, you would finally be able to write something. And we want ū— to help you almost do that.
...We also understand that the only way to truly remove an unproductive distraction is to replace it with potentially dozens of more highly productive distractions.
That’s why ū— provides the theoretically serious writer with an incomparably powerful range of options, preferences, and customizations that can literally be tweaked forever without writing a single word—let alone half a character.
Conlanging may be similar to this kind of trap: A language is such a complicated thing that you can fiddle with how it handles voice, aspect, and morphology forever, rather than making a decision and going with it. Which is the perfect excuse not to spend the time working on plot, character, or dialogue.
Nonetheless, I certainly do wish that many more writers would pay more attention to the quality of their linguistic writing. Coherent naming languages would be an enormous improvement over the standard practice in science fiction of presenting gobbledygook as language (as Huttese) or sprinkling words with apostrophes, Qs, and Xs in order to exoticize weak linguistic writing (as Punctuation Shaker). The recent introduction of conlanging to film is a good step in this direction, be it neo-Sindarin or Na'vi.
Or David J. Petersen's Dothraki, created for the HBO tv adaptation of novelist and executive producer George R.R. Martin's "A Game of Thrones". I wasn't impressed by the quality of the linguistic writing on the show at first; the names were mostly warmed-over, exoticized English. When the first words of Dothraki dialogue was spoken, I was amazed because the sophistication of the linguistic writing there was so much higher than the rest of the show. And so it didn't surprise me to learn that the producers had hired someone besides Martin to write the Dothraki language and dialogue.
But it helps demonstrate how different these types of writing are: solid linguistic writing, as in a good naming language, is good for a fantasist. But conlanging is a more specialized, time-consuming, (and non-remunerative) type of artistic writing.