They aren't doing it to force players to relearn classes, they are doing it because they are refining how the game works and plays. Blizzard has been quite explicit especially in this beta about what their thought process is and why they make some of the design decisions that they do. Perhaps try reading more of that and whining mindlessly less.
I'm not even sure why this is even a complaint now when much of the current work on Wod involves new systems and tweaks to existing systems. The real class tweaking and tuning hasn't even started yet and won't until after raid/pvp testing begins.
There is also the fact it is their game to design as they wish. You don't get to decide how classes play and never have and this isn't how any game has ever worked before so I don't know why Blizzard catches hell for daring to design the game like any other game designer would.
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Based on what exactly? Mindless hate?
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Why the fuck wouldn't it matter? What is on beta realms now is NOT the current state of Wod. A majority of builds never even get pushed to beta realms because they are tested internally. Every single time one of you doomsayers starts up moronic bullshit about the beta, the very next build that gets pushed makes all of you look like the mindless haters you are.