At first glance, they seem to be, and at lower levels I have a feeling that they will be. But D&D has always struggled to find a way to "encourage" people to play humans(something I'll never understand since most people I know run humans or humaocentric games). The whole fact that humans have essentially been "humans are pretty much whatever" has I think hurt them more than it's helped.
I think it would do better to define a few basic human "culture groups". They don't need to be as differential as races, but perhaps a nomadic plains people, a rugged desert-raiders people, a peaceful troupical-forest people, ect...
Actually, I think the key advantage is simplicity. If you don't want to manage a bundle of racial abilities, play a human.
While
some races can become difficult to manage with special powers and stuff like that, I don't think that the majority of abilities on DDN races really press into that realm. I think the rather bland Weapon Training abilities are the only thing that have ever left me confused, and that's solved if I just write stuff down.
Unfortunately, what does take a hit is the flavor. You no longer have a mechanical basis for the traditional trope of tougher dwarves, smarter elves and more agile halflings (at least, compared to humans).
I disagree, as I feel this was beneficial. Tougher Dwarf tropes can come from the fact that they work with rocks, rocks are hard, anything that works with them must also be hard. Elves live a long time, that's a lot of time for learning, hence, elves are smart. And so on.
Putting everything on a "well this race is special because humans are X and *race* is X+1!" It's really not that creative and just rather boring.
