I just rewatched the interview and what Ion said is the following (59:45): https://www.wowhead.com/news/preach-...iveblog-322060
Ion: ... some doomsayers wondering "is this gonna be like Warlords? Just one tier?" No, there's gonna be something epic and mindblowing up next after this and that's coming along great (Preach and Ion then: aka 9.2. stuff).
Ion basically answered what he considers as another WoD: just one tier. As 9.2 will be a second tier, they already avoided another WoD scenario with that. 9.3 isn't needed to make Ion's statement true. And something epic and mindblowing in 9.2 sounds pretty final as well.