Just gonna copy and paste my closed post here...
First, I do need to say people need to stop freaking out over this first off, they act like they're all broke and don't have jobs and live in their parents basements or are 13 years old. $50 IS a fine price for an xpack, and $60 is a very reasonable price for the time you'd spend at even MAX level, let alone the entire length of the game.
The reason they're doing this is to deter multiple accounts. If the game cost $60, aka WoW 1-85 being $20, WoD $40, it'd be the same exact price as the purchasable 90s, which could open up doors to all sorts of third party accounts on top of . People who hate stuff such as botting, Chinese farmers/goldsellers, multiboxing, account selling, etc...SHOULD ALL BE HAPPY ABOUT THIS CHANGE. It'd cost all these people MORE now to get to the points they are now, and will send prices even higher for their services, and could in the long run severely damage their businesses.
Blizzard has really started to take a steep "if you can't beat 'em, join 'em" approach to their two games that really include it. In WoW, gold is going to end up likely being only big for cosmetics and older gear via the BMAH. It already is ending up that way. Blizzard is also giving us little NPC followers who can do a nice chunk of professions and even go collect stuff for us and "run dungeons" and stuff like that to give us ACTUAL EQUIPMENT, GOLD AND MATS...really working AGAINST the botting community using similar tactics.
The Diablo 3 side of things went a little sour, and they removed the marketplace as they saw it really hindered their game, since a dungeon crawler is just that and having the market there essentially took out that part of the game for a lot of people, and leaving that market 3rd party was safer for the longevity of the game.
TL;DR - Cheaper price for non-botters/goldfarmers/account sellers to purchase multiple characters