Why does this thread exist so early? 1.12 isn't out yet. Also I'm pretty sure 1.13 won't be called "the block id limit update" as that would be a bad name. They said the block id limit update will be in 1.13.
As others have said, nobody on this forum knows anything about 1.14, and most likely Mojang developers may not even have a clear plan for what they are going to include in 1.14. Since this thread really has no real discussion value other than random speculation, I am going to lock it.