Will the pre patch send you to BFA zones or the Dragonflight zones as the starter?
The new night elf zone that’s a near copy / paste of the emerald dream is mostly empty except for portals, one to Felaras, that makes me suspect the long term plan is to make it a starting area.
They might be planing on a more classic like leveling experience with updated starter zones and maybe updating a couple of old world zones to make it more cohesive.
If you are talking about the pre patch event for gearing up it happens in three zones (events spawn on the half hour and rotate location) - duskwallow marsh, searing gorge and dragonblight (in northrend). The final event bosses are onyxia, ragnaros and arthas. Maybe you mean something else.
If you are talking about the new default levelling path I imagine it will be via dragonflight zones after TWW launches.
I reckon Dragonflight to stop people being called Champion of Azeroth all of a sudden (myself included as a SL baby).