DW 2015 does some jquery coding hinting auto completion. Are you saying they do not show in DW2018?
I've just done a simple test using Sublime 3 and DW 2015 and they seem to offer about the same level of code hinting completion.
that's true, and I agree, that emmet in DW has a lot of lack in autocomplete and user experience
OS , as the author propose... try to type ready in DW... nothing happen... in ST you'll get all the jquery ready function proposal...
11.09.2017-08.46.42
but there are plenty context where DW hang...
try to generate (a>img)*4 then hit TAB, now place the cursor in multiline in between the a tag and the img tag... now type i and hit tab... in ST you'll generate the new tag on each line not in DW
and the list is really long...
so as the author, since many years now, when I have to really dig into the code... I swap to ST... and that's also why since many years I ask to folks @Adobe to bring back in the prefs settings (category File Type/Editors) the declaration of the external code editor as it was by the past and removed since CC. This setting allowed us to have a real roundtrip from an external code editor (of our choice) and the DW UI