I have no interest accessing those features via a XML editor. It's faster to an extreme to access OTF features via the methods that are available in the user interface within CorelDRAW and Adobe Illustrator.
I figured that would be the response, or something along those lines. Regardless if you have a desire or not to access them outside of the palette, the fact is that there is another way to access them. Don't use it, that's fine, but that doesn't mean that there isn't another way to access them beyond the font palette.
As to the speed of it all, that's actually debatable. The biggest point is knowledge base of the user and the comfort zone of the user(usually both of those are tied together).
New stuff is always going to be slower as well until one gets the hang of it.
It's a very powerful feature, one that doesn't exist (at least up until the versions that I have) in Ai and DRAW(for actually obvious reasons). Have to remember that XML Editor gives all access to the individual file itself. Anything that Inkscape can't do directly via GUI, more likely then not, can be handled there. And this is where info from plugins is also stored to be retrieved later as Inkscape doesn't destroy markup that it doesn't recognize (unlike Ai and DRAW).
As to the GUI features, they are limited to what was available to CSS (again, web centric format) at the time that they froze major features. Could see about getting 1.0 Beta (if you haven't already) and see what they have in there, if it has changed. I have a copy of it, just use .92 far more as 1.0 is Beta.
By the way, there is another problem involving text I forgot to mention in my first response. Anyone who uses Adobe Creative Cloud will not see any fonts they sync from the Adobe Fonts service within Inkscape. Other applications, such as CorelDRAW, will "see" those synced fonts. I don't know why the fonts aren't visible within Inkscape.
Interesting thing about the XML Editor, even if there is a font substitution that goes on. It still shows the original font family in the editor itself. Now it doesn't show the font on the canvas itself as the legitimate font. You'll see it in the PDF preview on import (although there is no warning about font substitution going to happen, just an option to tick if you want substitution to happen when it is necessary), but it won't bring it in on the canvas after import. But Inkscape should be able to "see" the font.
Now, with it not being able to bring it to the canvas even with PDF compatibility (which I always have to on, never really changed the default), I would say is a limitation of the software.
I used Comic Sans (I thought all y'all would like that) in an Ai file in my Windows VM. Inkscape on Linux was used to open it up(I used a font that I know wouldn't be on my Linux box) and as you can tell, the text that appears on the canvas is
not the font family name listed in the XML editor (I have the cursor in the screen shot over the appropriate area). Now, I don't know if that will work on the CC specific fonts as I don't have Adobe CC to try that out.
The XML Editor is a powerful feature. Use it or don't, that's up to you.
Of course, could always see about copying the file. Renaming the copy as whateverFilename.txt and then opening it up in a text editor and search for Font and should be able to see that info just as well, but a little longer of a process.