I think it is fair to preface the answer with the question to understand what Ion meant. Especially the full transcript (I just jotted down from the video, so excuse typos.
It looks like time runs differently in the Shadowlands than in Azeroth. Maybe that’s why Uther, Kael’thas and other characters have been there for ages when it has been just a few years in Azeroth. How does time go by in Shadowlands and what does that mean for our characters.
So, I had to, this is something I’ve actually been actually asking our lead narrative designer Steve Danuser about because I had this same question a couple of weeks ago. The answer is complicated. It’s not like some science fiction movies where in a black hole or something time just moves faster. But time is different in the Shadowlands. Time is a construct of order and structure. And things in the Shadowlands are more chaotic in a lot of ways. Think about how times moves in a dream where there isn’t necessarily a fixed amount of time or things move and bounce around. So the souls that have been in the Shadowlands, to them it might feel like they’ve been here for a very, very long time as they’ve gone on their own personal journies of discovery and evolution. But it’s not necessarily 2x faster or 3x faster, time is different. And what does that mean for our characters? Well that’s something we’ll have to see as we come out the other end.
The way he talks about it more just seems like an explanation for how characters talk about stuff (much like Turalyon and Alleria were given nether time dilation for A Thousand Years of War, but it didn’t change much either).
I do think his last statement teases the possibility of a time skip, especially if he felt the need to ask Danuser to explain. But I think more likely a way of making the characters seem like they’ve dealt with a longer time in the afterlife.