You know, I'm really sick and tired of people QQing about old content rehashes, the only reason they can give being "Omg, I have/haven't done it before, therefore it's old and is below me".
First, content rehash, if you want to look at the bigger picture, is rare. Yes, it happens, but it's not like every new dungeon/raid we get is a rehash. Personally? I like seeing old content revisited. Otherwise you'd never see it again (the sticking point being some people never want to see it again, I suppose).
Secondly, and much more importantly, content rehash allows blizzard to churn out content for you guys in a very cost effective manner (believe it or not, blizzard does not have constant access to infinity billion dollars as you guys seem to believe). Yes, WoW is (seemingly, I haven't looked at any public financial reports of late) profitable to Blizzard. Mad props.
Lets take a look at their not so profitable projects, shall we?
• Battle.net - Pretty sure this is still free worldwide, and you can still play SC and D2, as well as SC2 on this service for free. Servers ain't cheap, neither is the bandwidth used when playing on them.
• WoW Servers - Given how stable they are for the most part, I'm willing to bet we're running on some pretty pricey hardware, and some fat pipes. Also not cheap. I'm willing to bet the hardware alone would cost more than most of you make in a year.
• Diablo 3 - Still in development, therefore losing money for Blizzard. Yes, they'll make millions when it launches, then you guys will be playing on Battle.net...for free! Most likely a financial loss in the long run, and definitely a financial sink hole right now.
• Project Titan - Yet another project in development, this one probably Early Alpha - Mid Alpha. Not making Blizzard money in any sense of the word, and probably has a fairly large dev team behind it. I'm willing to bet the baseline budget on this is $10m+ (most games usually go over their initial baseline estimates).
• SC2 Expansions - Oh look, more development.
• Warcraft Development - See above.
Everything I listed above costs money, and none of them are immediately profitable (D3, SC2 expac and Warcraft patches being the most realistic potential income). While Blizzard probably makes money hand over fist from all the subscribers they have, I'm willing to bet alot of it gets immediately put back into the company somehow, before even looking at paying the people who work there. After employee expenditures, anything left over is the profit Blizzard makes. Not profit they're bound to reinvest into their games, mind you (I'm willing to bet some of it is reinvested, but that's not the point). Profit is calculated out and reported to shareholders (as ActivisionBlizzard is a publicly traded company, after all) and business partners, who, ultimately, control the fate of the company.
Want Blizzard to cater to you? Buy stock. In the meantime, enjoy the content Blizzard is putting out for you while you wait for the 'real' content.
As for my personal opinion, I can't wait for redone ZG/ZA to hit live servers. I loved them at 60/70, and I can't argue with free Maelstrom Crystals :)