This is exactly what they did, and they pretty much stated that as a fact. Their goal was to allow players to build any character they want and use any skills they want and still be effective to try to minimize the min-max builds. The fact that you had to follow exact guidelines to build your character in D2 or else it is a failure in Hell is what they are trying to avoid. There are upsides and downsides to this. If you think about it, they didn't really dumb down the game, they made it more complicated, because now you have different builds for each character type that could be relevant and certain items with specific stat bonuses on each that would be required to max your characters potential. They essentially took 5 'classes' and made an infinite amount of possibilities out of them.
Now I am sure there will be some builds that are more effective then others, and those will be fleshed out, probably within the first week, but I think the attempt to diversify the classes is a noble goal in development. It was annoying to see nothing but firewall/blizzard sorcs, hammerdin pallys, and whirlwind/shout barbs and nothing else.