Blizzard have written into the game of World of Warcraft, significant changes to how the game is played. Many changes are fantastic if you know the earlier version, with new concepts, new storylines, new weapons and spells, and newer, simpler ways of doing things.
One game construct I feel a burden, is the linearity of the quest chains. You need to run through each quest, one after the other in order to gain the endgame goals. To make the end game harder to reach, repetitive tasks have been introduced into the quest lines, with a needed requirement to complete one chain, before you can start on the next line.
If you fail to enjoy one section of the game, you will find yourself excluded from a lot of later game content, this I find, a little unfair and would like to point out other games in the world of MMO RPG's enable multiple paths to reach end game content, and one, Eve-Online, No path, you can choose how you play to reach an end game you decide upon.
Right now, a lot of things are shared with my other characters on the same account, account sharing is a good thing as it means that I don't have to run the same content over and over to have , say a special flying mount. Sadly, Blizzard have chosen to not include some content from being account bound, so if I want to ride my new mount with a second character, that character will have to run through the same long winded dailies until they have enough rep with the Flying Serpents to be able to buy the licence to fly.
I would love to see a small satchel in the bank, accessible only to my account so that I could share heirlooms with characters on other servers. After all, my pets, mounts and achievements are considered shared across all my account characters, so why not heirlooms.
I find myself limiting the number of characters I am progressing to level 90, there is so much end content to work on, well, read, 'daily grind', that with a screen full of characters, twelve to sixteen hours a day online playing a game is disturbing in the reality of things.
One can simply have too much World of Warcraft in their days timeline.