I seriously doubt we're getting any timey-wimey shenanigans in 4.5 or 5.x because if it involves exploring parts of the ruined world as zones it would necessitate having some kind of time portal just for the sake of traveling back there to gather or do hunt marks which seems...awkward from a narrative standpoint.

I feel like it's more probable that we're just going to travel to the first shard if they want us to experience a ruined world and get a glimpse at what would become of the source if things continue as they do.