Disclaimer: These are all PTR changes, so some might not make the game. The mount stuff is already confirmed, though. Also, I didn’t post the whole list. I just put the important shit.

Source: http://www.worldofwarcraft.com/patchnotes/test-realm-patchnotes.html

# Chef’s Hat is now superior-quality and allows the chef to cook faster.
# Transporter devices are no longer classified as trinkets and can be used directly from your inventory.
# Doubled the duration on Nitro Boosts.
# Significantly reduced the cooldown on MOLL-E.
# Mote Extractor now has innate tracking for gas clouds while it is in your inventory. Tracking of gas clouds has been removed from goggles.
# Players with 300 or higher cooking have a chance to find a Waterlogged Recipe in the Bag of Fishing Treasures awarded by the Northrend fishing dailies. This item can be traded to other players and rewards several Dalaran Cooking Rewards when turned in.
# There is a now a 20-minute timer in Warsong Gulch. After that time, the team with the most flag captures wins. If this would result in a tie, the team that captured the first flag wins. If neither side has captured a flag, then the game ends in a tie.
# Players will now be awarded experience for completing objectives and actions that yield honor in Battlegrounds (honorable kills not included).
# Players who do not wish to gain experience through PvP can visit Behsten in Stormwind or Slahtz in Orgrimmar – both located near the Battlemasters in either city – and turn off all experience accumulation for the cost of 10 gold.
# Disabling experience gains will prevent a player from gaining experience through any means available in the game.
# Players with experience gains turned off who compete in Battlegrounds will face off only against other players with experience gains turned off.
# Behsten and Slahtz can reinstate experience gains for players, for a 10 gold fee of course. Any experience that would’ve been accumulated if experience gains were enabled cannot be recovered.
# The cast time for summoning any ground mount is now 1.5 seconds, down from 3 seconds.
# Apprentice Riding (Skill 75): Can now be learned at level 20 for 4 gold. Mail will be sent to players who reach level 20 directing them to the riding trainer.
# Journeyman Riding (Skill 150): Can now be learned at level 40 for 50 gold. Mail will be sent to players who reach level 40 directing them back to the riding trainer.
# Expert Riding (Skill 225): Can now be learned at level 60 for 600 gold from trainers in Honor Hold or Thrallmar. Faction discounts now apply (Honor Hold for Alliance; Thrallmar for Horde). Flight speed at this skill level has been increased to 150% of run speed, up from 60%.
# Artisan Riding (Skill 300): Faction discounts now apply (Honor Hold or Valiance Expedition for Alliance; Thrallmar or Warsong Offensive for Horde).
# Flying over Dalaran and Wintergrasp is now possible so long as players keep a healthy distance above the ground.
# Blessing of Sanctuary: This blessing now also increases stamina by 10%. This effect is not cumulative with Blessing of Kings.
# After much quiet contemplation, rogues now possess the ability to learn how to use one-handed axes.
# Chain Heal: Jump distance increased to 10 yards. In addition, the amount of healing now decreases by 40% as it jumps to each new target, instead of 50%.
# Ghost Wolf: Can now be learned at level 16. While in this form, snaring effects may not bring the shaman below base normal run speed.
# Macros and scripts will no longer be able to target totems by name.

My account has been inactive for about two months. But Blizzard assures me I’m still the best Paladin in the game. Bet.