Here is a breakdown for what players can initially expect to see in the first phase of Dragonflight alpha:
Phase 1 Zone Experience: The Azure Span
New Race and Class: Dracthyr Evoker
Dragonriding
New Interface HUD Revamp
Talent Revamps for Death Knight, Druid, Hunter, Priest, and Rogue
Professions: Alchemy and Blacksmithing
Full details on the following phases will be shared as we get closer to them, but here are the current plans for the zones:
Phase 2 Zone Experience: The Forbidden Reach
Phase 3 Zone Experiences: The Forbidden Reach and Waking Shores
Phase 4 Zone Experiences: The Forbidden Reach and Thaldraszus
Phase 5 Zone Experiences: The Forbidden Reach and Ohn’ahran Plain
Phase 6+ All zones are expected to be playable