[guineapig]

Also, no maps!!

Well there are maps in the newbi zones (weren't there in classic but that's a client issue).
But once you get out there you will often have no idea where you are going or what's to expect.

You don't have a compass... well you do but you have to gradually skill up the ability to sense your own direction.

You have to learn how to swim. Initially if you jump in water you will be as slow as molasses and need to swim ALOT to get good at it.

Same goes for any skill really. If you are a warrior you have access to 1 handed slash, blunt and pierce as well as 2 handed slash, blunt and pierce. Any skill you don't use will be that much more difficult to use later on on life. Casters have a similar issue with different types of spell casting. Usually not a big deal but it can surprise you if it's your first time playing.