WoW Classic Season of Mastery | What can we expect?

The timeline will be 12 months but it will be with cycles. These servers will have 6 phases, but phase unlocking will go faster.

• Phase 1
  Molten Core, Onyxia, Maraudon, PVP Honor System, and Battlegrounds
  
• Phase 2
  Dire Maul, Kazzak, Azurego
  
• Phase 3
  Blackwing Lair, Darkmoon Faire, Darkmoon cards now can be looted
• Phase 4
  Zul'Gurub, Green Dragons
• Phase 5
  Ahn'Qiraj Warr effort
  At the end of the event, the AQ gates will be open for players
• Phase 6
  Naxxramas
  Scourge Invasion
  

Blizzard decided to do raids more competitive and harder for players.

• World buffs disabled in raid dungeons
• Restoring some game mechanics for bosses, which were removed in the previous release
• No boss debuff limit
• Increased boss HP
  

Increase XP rates. It should be like 1-60 in World of Warcraft: The Burning Crusade

Meeting Stones now will work like Summoning stones
Increase Mining and Herbalism nodes

Mage boosting Changes:
Blizzard was removed mage-boosting in dungeons. On PTR they are made changes and added immune to root and snare effects to some mobs.

• Significantly less experience is now awarded to players who kill a creature while in a group with one or more players who are at a much higher level than the creature that was slain
• Stratholme – All Undead creatures in Stratholme will now gain an immunity to snares 30 seconds after entering combat and gain immunity to roots after an additional 30 seconds of combat.
• Maraudon – Many creatures in Maraudon will gain an immunity to snares 30 seconds after entering combat and gain immunity to roots after an additional 30 seconds of combat.
• Mauradon – 30 seconds after gaining immunity to root effects, enemies gain 50% increased movement speed.
• Maraudon and Stratholme – Any type of crowd control (except snares or roots) will reset the snare immunity, root immunity, and speed buffs.
• Zul’Farrak – Zombie Trolls in Zul’Farrak now drop fewer lucrative treasures. Most of the loot previously dropped by Zombie Trolls has been redistributed to other enemies in the dungeon.
  
  

The new hardcore mode in World of Warcraft Season of Mastery!

Blizzard added 2 new npc in Undercity and Ironforge.
These npc's can give you a buff Soul of Iron.
Dying with the Soul of Iron buff will immediately give you the "Tarnished Soul" buff and your Soul of Iron will physically spit out of your corpse, quite a sad sight. The Tarnished Soul debuff reduces all of your stats by 1%. Dying additional times does not increase this percentage.
You can dispell this buff/debuff in any time if you are not interested in hardcore-mode by speaking with these npc's.

It is just the first part of changes, but I think everyone wants to try it!

See you in beta!