In my experience it is true; of course some areas may require more detail and attention and tweaking and summoning the Evil Red Text in LyX.
In your case, it seems you are not really writing the text... You are making cosmetic adjustments. And it is fine but it should not be done up front, IMO. As for ligatures, TeX should handle ligatures automagically, but I took that as a general point and yeah, I agree -- one can always find things to tweak.
Process-wise, it is better to "just write". Most of the cosmetics is taken care of by LyX with minimal effort. Add a comment for something to check later. Make the process iterative, if you try to write each line as production quality from scratch, I doubt you will ever finish.
I was being a bit facetious. I just know I'm not the only person out there who WASTES an enormous amount of time fiddling with LaTeX instead of working.
For pure composition, you are certainly correct... do not write in the Tex editor... Just compose with WORD or something, and then take care of the formatting in Tex at the end.
(Regrettably, though, I am involved in several projects where the composition necessarily has to be in the LaTeX editor as the format and cosmetic adjustments are very important.)
It seems a lot of the helpful questions and answers on the various LaTeX websites come from some PhD student working on his dissertation. I kind of smile with sympathy at their earnest questions about how to print an equation upside-down and backwards in a table cell while using multicolumn (just a silly example...) I know whoever was writing the question was, like me, surfing the internet and focusing on formatting instead of getting back to work and finishing the damn dissertation.
In your case, it seems you are not really writing the text... You are making cosmetic adjustments. And it is fine but it should not be done up front, IMO. As for ligatures, TeX should handle ligatures automagically, but I took that as a general point and yeah, I agree -- one can always find things to tweak.
Process-wise, it is better to "just write". Most of the cosmetics is taken care of by LyX with minimal effort. Add a comment for something to check later. Make the process iterative, if you try to write each line as production quality from scratch, I doubt you will ever finish.