I believe the paid class change question is a very interesting question. Someone asked the queue on wow insider if there would ever be paid class changes and Anne gave the perfect answer that I 100% agree with. But I feel I must play devils advocate here for a moment and argue why it should be an option.
Devils advocate time, here goes.
Three reason why there should be a paid class change.
1) Leveling doesn't teach you anything.
In theory is should but it really doesn't. Sure, some people might learn some stuff but most will just power through it not learning much of anything and if you look at it, it is designed that way on purpose.
In my personal assessment I would say leveling is 80% just press through it with any buttons that do damage, 15% minor challenge where you might need a minute to think about it, 4.8% I am definitely going to need to use some of these other abilities and 0.2% holy crap I wish I knew how to play my class better because this seems impossible.
You can level from 1-90 without ever leaving the comfort zone of the 80% type quests where you can just power your way through it. If a quest comes along that you have an issue with, abandon it and move along to something else that is easier. Which is exactly what most players do. They will say, I will come back to that later when I am stronger and then out level it so they never do.
Admit it, we all did that when we leveled too. It is nothing new. I passed on many a quest back when I leveled my first character or waited to see if I could get a group to do it. But leveling is not like that any more for the most part. So where I was running into that all the time, new levelers might run into it once in a rare while.
This faster leveling, easier level, leaves people with less opportunities to learn how to play their class. It might very well not be that they do not want to learn, it could be a case of they never have the chance to learn. Giving people the easy route with fast leveling also gives them the ability to skip zones when the quests start to get harder at the end of the quest line because they are basically out leveling the zone anyway.
2) Blizzard wants you at the end game.
Everything is designed for the end game. Even PvP which is the only part of the game that has the potential to be awesome at every level gets pushed to the side for reasons of balance at 90. That is why the leveling is faster. That is why it is harder to learn while leveling. They do not want to put a bunch of roadblocks in the way.
The design theory at work here is that leveling is something you want to do. End game is the rat on the wheel moment. They feel as if they can keep you coming back day after day and paying month after month if you are on the wheel at max leveling doing the gearing grind over and over for whatever it might be. Gear, rep, you name it.
So the faster they can get you there the more likely they are to keep you. They figure it is easier to keep a 90 interested than it is to keep a 25 interested and it is better to spend their time trying to keep everyone interested if they can design content for one part of the game and make sure everyone is there. That is why they push everyone to 90, so everyone is in one neat pile and they can design for that pile and that pile alone.
3) Learning a class at 90 is easier than learning a class while leveling.
Yes, I just said that. Flame on.
When leveling took longer you really got to know your abilities because you spent a lot of time with them. When leveling was harder you really got to know your abilities because there were more times you actually needed to use all of them. Now, not so much.
They can give you an interrupt at level 32 but by that point, unless there is a real reason to need one, you have already learned to just kill things before they cast the spell that will hurt you. They give a hunter misdirect after they have spent countless levels without it. So they might just over look the ability because if it was really that important they would have had it already and they made it this far without it so they do not really need it. Why not give it to them when they are young so "if" they are going to learn how to use it they can get used to it instead of waiting until they learned how to play without it so they ignore it?
Quick & easy leveling means you really do not get the chance of learning how to use abilities. You can miss a hell of a lot while leveling. Trust me, as someone that brings people that never raided before into raids, I often need to hold their hands and explain what 90% of their abilities are because "I didn't even know I could do that".
Hop over to icy veins, noxxic, or countless other resources and look up a rotation. It will tell you all the goodies a damage dealer will need to use, all the cooldowns a tank has, all the types of heal a healer has, and it will tell them the order they need to use them in, tell them what proc to look out for, when to hold off or to let go, which abilities are situational, which are things you should use when called for in a raid.
Everything you need to know about your class can be learned in 10 quick minutes of reading. Practicing it and getting better at it is on your hands. But you will learn more in 10 minutes of reading than you did your entire time leveling.
I've seen learning while leveling confuse people. I've also seen learning at 90 be a great success.
I never healed on my shaman once in my life when I decided to do it at 85. I looked up some shaman resources online, read some guides, looked at my abilities, made some mouse over macros and I was healing that same day. Not very well in my crap gear and having never even attempted it before but well enough to make sure everyone in a 5 man could live. And that was when the 5 mans in cataclysm were still pretty brutal on most players.
I had never done the shadow rotation in my life but needed it to level to 90 as disc just wasn't cutting it and it was taking to long for things to die. I looked it up, read the guide, powered through 85-90 like it was nothing. Same for switching to elemental on my shaman. Got tired of collecting so many sets of gear I figured I would go elemental with my shaman and just quest in my healing gear as it would be decent enough for it. Looked it up and even though I never played one before that I have absolutely zero issues with being elemental.
If you are the type of player willing to look things up, learning at max level is not an issue at all. It is super easy to learn how to play a class at max level. So that should never be considered an issue as to why they would not allow class changes. If someone is bad at one thing and changes their class, they will be bad at the other thing too. It will not create more bad players, it will just turn a lot of bad hunters into bad warriors and a lot of bad paladins into bad monks. If anything, it might actually make some people better. Some people might just naturally be better at another class or maybe, just maybe, they read up on the class before deciding to switch to it. Class changes might actually mean more people knowing how to play, not less.
In closing, while I do agree with Anne as to why it will never happen and actually think it should never happen it was fun to play devils advocate a bit right there. What do you think about it?
In that same vein I would love to see a character copy offered.
If you have a max level hunter on one server, you can make a copy (of level only) on another server for a fee. None of their items will be copied and they will only have a basic set of blue gear appropriate for their level when created, but they will be at the same level.
Now that is a service I would not mind seeing come to the game and surely would rather that over a class change any day. I already have every class, what do I need that for anyway. ;)