Yeah, but everyone was expecting that her character would appear in TW3 and, in the end, is what happened, so, I wouldn't put it as an example. I'm agree with you on Yaevin but his character was properly replaced with Iorveth. At this point, I would be glad if they had done the same with Isengrim. My complains are not just because of Iorveth but the whole scoia'tel plot, which was much more important and there is no word about it in TW3. Also, Yaevinn had a line in a dialogue with Iorveth back in TW2.The same happened to Shani in Witcher 2, she played a major role in TW1, but until that journal note was added in the enhanced edition, she was not even mentioned in TW2. However, unlike in the case of Iorveth, I am not sure if it was ever promised that she would appear, and at least she was brought back in Hearts of Stone (which even includes a kind of simulated save import that affects a handful of dialogues). For Iorveth, it seems we get the card game, but who knows what might be in future games..
Being realistic, TW saga is finished and a future game about this world it's not just unlikely, it's impossible from my point of view. TW3 was the end and sadly, those who chose Iorveth paths were completely ignored