Time for my 2 cents, I quit in MoP simply for the reason I was there since vanilla and quite plainly just couldnt be bothered with it anymore. Too much time spent doing things ingame where as I could just do other things. Note: Thats my personal opinion, its a good game but I just couldnt be bothered with it, so props to it but..yeah.
1: The reason I personally find it crap that you can insta boost a char to level 90 with the simple motion of waving your wallet is because I always believe in games if you want something..you should earn it. Of course it can be debated 'well, I did earn it, I spent my hard earned cash (or, I annoyed the hell out of my parents for 3 hours till I got their credit card, each to his own.) and worked for it physically/mentally. Yes, that debate can go on and on, nevertheless out of personal belief I think stuff in games, should be earned ingame. As spoken, my opinion.
2: Ill say about 90% of the folks who use this will most likely do it for a raiding alt or such, so they have a concept of the game/raiding/builds etc. Through this by 'most' it wont be a prob, get together with some friends, jump in, play around with it for a bit and grasp the class/spells/cooldowns. Though of course theres that 10% who are completely 'flawed' then, who have jack all clue what they are doing and will run into a brickwall face first.
3: My personal opinion on the matter...I donno if its changed at all but I do remember that its...Ill say, mind numbingly easy to level up to 90. If you make a new char Friday night, and binge it over the weekend, (with all the exp boosts etc..) your already level 90. Voila, if you dont have all the exp boosts you'll still be done with it before the coming Friday if you have a clue of what your doing (an added bonus is you'll learn your rotation properly and how you can best play/be of assistance with that class...the point which your actually trying to get to).
Now if I weigh all that out (especially point 3), if someone wants to throw their money at the screen, be my guest. Its not my money, so I have absolutely no problem whatsoever with it. If someones a nab in a raid (theres always one) I 'usually' gladly gave them a nudge in the right direction, unless they were an impolite prat then..screw them^^ haha.
Long story short, each to his own, Id personally rather save those 60$ and spend it on rent/food/other things and just binge it over a weekend if I really want it that badly. If someone else wants to pay, knock yourself out, no skin off my back.