Not just the best WoW expansion but thee best MMORPG that ever was and very probably ever will be.
In the end it turned out to be the only expansion that kept me playing right from the start to the very end, due mostly to the wide variety of things to do and the very addictive gameplay that came with it that yes made things easier but at the same time made it much more accessible to a wider audience.
The new continent - northrend is divided up in to 8 sections with importantly two starting areas rather than just one so theres plenty of room to quest and level up and that trend continues throughout the expansion with players able to do different areas and quests to level up which is great for replay value with alts.
The questing is overall a very good experiance, the difficulty level is perfect as mobs have a very well balanced damage done/taken limit that means its not too easy but that player skill can still be rewarded by nailing all the right moves to escape unhurt. The same is true for the instances added in and during this expansion, they reward good groups but are still tuned so that less able or geared groups can still get through them without becoming frustrated and giving up.
There really is too much in the expansion for me to go through it all - the Death Knight class and professions an class changes ect. All i can say is that this has the balance perfect for the large amount of players who are not hardcore 24/7 players, its a shame then that all of this is very much retrospective as things have been changed that in my honest opinion spoil the game to how the game was back in this era.