I definitely think 4e has taken a step back...in a good way.
Basically, in 3e, the designers pushed mechanics in some new and crazy directions. They were great ideas, very forward thinking. But after trying some of them we all experienced some of the downsides. The designers realized that some of those new ideas had more drawbacks then benefits. In 4e, they attempt to keep the parts of 3e that worked, and then revert some ideas to earlier concepts.
Basically, in 3e, the designers pushed mechanics in some new and crazy directions. They were great ideas, very forward thinking. But after trying some of them we all experienced some of the downsides. The designers realized that some of those new ideas had more drawbacks then benefits. In 4e, they attempt to keep the parts of 3e that worked, and then revert some ideas to earlier concepts.