If it would not be possible to make a wikitext version of the CX tool, it would be at least useful to provide a way on the saving to make finalisation of the code in wikitext editor rather than save right away. I am speaking about an option now, not about changing the standard behaviour, just to be clear about it.
CX tool does not support templates and other stuff which normal articles include yet. The code produced via CX needs some tweaks in many cases. The most common is to add an infobox or other templates, or to fix some stuff which was done badly in the visual mode (e.g. half of a word working as a link instead of the whole of it). Sometimes even abuse filters are triggered. Experienced editors always start to do that second edit fixing stuff after the initial creation one. Sometimes they end up being slower than other editor who has noticed the article creation in RecentChanges and raced to help with fixing it. The help is always welcome, but in this case it would cause an edit conflict for the user who created the article and was making their second edit. It would also rather worsen opinion of users about each other, as one will think that another is not even able to use templates, while the other will be annoyed that that other guy could not wait another 2 minutes to let him finalise the layout and other tweaking.
This can be avoided if an experienced editor doing translation via CX could make the finalising tweaking of wikicode before actually saving the article. It is ok if it would be a point of no return with several warnings like "By pressing this button we are going to convert the article you have prepared into wikicode and you will not be able to revert back to the CX translation interface. Do you wish to continue", experienced users will know what they do, but they will get a way to not be nervous that 5 min after the creation when they have to rush to fix the article right away before others have noticed it and, what worse, have even fixed it.