Regarding this whole Witcher versus Dragon Age debate I like one of the comments on Joe's video; that comparing the two is like comparing Lord of the Rings with Game of Thrones, sure there are similarities but ultimately they are two completely different games within the same genre. I really enjoy both fantasy settings (DA and Witcher) and their respective games, but for totally different reasons. I think we should all be happy more than one company make great RPGs, the more the better I say (and hopefully not go of another rant about the two companies once Mass Effect 4 and Cyberpunk 2077 are close to release)
I would personally never compare Dragon Age with Skyrim. I think what Skyrim did for the genre is move it toward more open world settings, but my experience with Skyrim is that it counted on you as the player to create your own story, which it did a fantastic job of. If you entered the world of Skyrim and expected a full connected world where choices matter, you were in for a huge dissappointment. Bioware games have a history of giving you a narrative and then have you affect that story through your gameplay.
The huge question still to be answered is whether it is possible to create a deep connected story where your choices have a lasting effect in an open world setting, both Bioware and CD Project Red are hoping to accomplish this. Personally I hope they both success as the RPG genre will be better for it, but it is a daunting task to be sure.