It's the Ideal Time to Obtained Your WoW Achievement
With the WoW Patch 6.0.2 went to live on Public Test Realms, it's just a matter of time when we'll see it drop live. A lot of things will be gone with this patch so if you still have not yet obtained your achievements and/or titles than now's the ideal time to do so.
Chalenge Modes Gone
All of the challenge mode achievements are becoming Legacy and Feat of Strength achievements, with all of the rewards other than the armor sets and teleport spells becoming account wide.
Bronze: The Undaunted title will be unobtainable and account-wide.
Silver: The mounts will be unobtainable and account-wide. If you have at least one of the mounts, all four of the mounts will be unlocked.
Gold: The transmog armor sets and teleport spells will be unobtainable and remain char-specific. The Gold guild achievement that rewards a pet will be unobtainable.
Siege Of Orgrimmar
Difficulty changes are under way in 6.0. The Ahead of the Curve 10 & 25 cheevs for killing Garrosh in Normal difficulty will not be obtainable. These rewarded the Kor'kron War Wolf mount. The Cutting Edge 10 & 25 cheevs for killing Heroic Garrosh will no longer be available. The Kor'kron Juggernaut mount that drops from Heroic Garrosh isn't going away, but after Warlords goes live, it's drop rate will be rare instead of Guaranteed. Warforged Seals have had their weekly cap removed.
Heirlooms
Will cost gold instead o Justice Points. Prices are 500-1500g / item and an additional 500-100g to upgrade.