Honestly with Yen or Triss I do not think I would have purchased the premium path for the Journey.I think it's great that they didn't go for the MOST OBVIOUS and already very well known characters like Triss or Yennifer or smtn like that, instead they went for a less covered character that is still important and interesting. I mean the Witcher universe is much larger then just the 5 main characters that revolve around Geralt lol.
I did not skip a Journey thus far, however I do not think I would care about a journey centered around them.
Also Alzur is in some way (one of) the most important character(s) in the Witcher world, considering he is at the core of the creation of the Witchers AND responsible for some of the strongest Spells.