During this year's Midsummer Fire Festival you have a chance at getting a pet from the satchel you're given for completing the Lord Ahune event. You can only get a satchel once per day for your character. A pet collector friend of mine said they were happy about that because otherwise he would run the instance multiple times each evening. He said he was concerned he may not get it, but didn't seem overly so.
For Cataclysm the plan is to have one lockout for 10-man and 25-man raids. People are QQing about this saying they won't be able to raid as much. But apparently, through forums or some other method, the developers heard many complaints that players felt they had to raid both even when they didn't want to.
Limited attempts for raids led guilds to level multiple alts that would give them the tries they needed to stay competitive (and ultimately "win"). One high profiled guild said enough is enough I decided to quit raiding in the type of environment that required that. But apparently not enough followed suit and I don't think they are going to develop limited attempt raids in the future.
And almost forgotten by many, in PvP, you could play the game 24 hours a day at an attempt to reach High Warlord or Grand Marshal and Blizzard removed that honor grind because not enough players could control themselves to not do so.
"Remember to take all things in moderation (even World of Warcraft!)" is a tip that is sometimes displayed on the zone-in screen of the game.
I appreciate Blizzard's attempt to be responsible purveyors of their...craft. They may have to do so with us kicking and screaming but in the end let's hope we realize it was for the best.
1 day ago