Hi, long time reader, first time poster on these forums.
Just to add my two pence, I don't think all you people saying to just run low level content to get the 'levelling' experience really understand, so I'll try to explain my perspective. I've levelled a few classes myself, and I vastly prefer starting at level 1.
I prefer it not because of the grind to max level, or because I particularly enjoy running lots of low level content.
I prefer it because there's no mess. You have your first skill, and as you level you get the rest one by one. As a result, you learn how and when to use each skill individually, you notice what works well together, and you choose where you want that skill on your hotbars.
Picking up red mage at 50 was hard, because there are so many buttons and you end up spending a while reading what each does, what you should combo, and reassigning everything to where you want it.
It's not about wanting to run low level content, it's about not wanting to be overwhelmed with a lot of buttons to press and no experience in how to best utilise them.
You may think that the majority don't like levelling because you mostly hear that opinion, but the people who do enjoy levelling don't make threads praising it, they just get on and do it.
Just because 5.0 brings new classes doesn't mean they shouldn't start at the bottom. If anything, a class that starts higher than level 1 is offering you a freebie, because there is no good reason you should just get a class handed to you on a silver platter.

So that's my thoughts, I hope you understand a little better why people might want to start at level 1, even if you disagree with some or all of what I've said.