When I finally realised that I had to talk to the Urshilaku wise woman to finish the fourth and/or fifth trials to update the Archcanon's dialogue, I immediately went to Vivec to fetch Wraithguard. Even though I have gone through all dialogue with Vivec, I have not received Wraithguard, although I can steal the Unique Dwemer Artifact from him and start the back door quest for Wraithguard.
I reckon that all that's needed is a good look through Vivec's dialogue, as for now, I will have to give it to myself through the console. (Unless it's not truely necessary to have Wraithguard to wield Keening and Sunder)

#1
It seems that Wraithguard is now light armour, while it used to be heavy, and it's worn on both hands, while it's one glove. It's worn on the right hand, so the left needs fixing.