I think people concerned about perfectly duplicating Word's layout should realize a few facts.
Word's layout has changed over the years.
Word's layout depends on the specific metrics of the fonts involved. I believe that the metrics of the usual fonts may have changed slightly over the years.
Word's layout depends on the specific printer driver you are using, since it modifies the font metrics depending on the printer driver. (ISTR there's a way to turn this off recently, so add this to the above.)
Word users exchanging Word documents between each other can't depend on the document looking the same way on each machine. This has been a problem for Word users for years. Since these problems are inherent to the design of Word. A Linux project to exactly duplicate Word's rendering engine will still have problems with a document looking different than it looks to the person who wrote it using Word. That's why I think that it's more important for a Word formatter to try to format things well, rather than try to match a target's evasive maneuvers.
There is a place for a formatter which always makes a document the same way. Word users have been asking about this for years. (WP users too, once it started using Windows, I think.) This is the same reason that Knuth went through such pains to make TeX's output the same wherever, on whatever. But a formatter can't do this and match Word's erratic output.