It's certainly a problematic restriction, as things stand. Unfortunately, Creative Commons appears to be going down the path of merely defining it more crisply when, in my view, the better approach would be simply to eliminate it entirely.
First, a little background. Creative Commons licenses are a sort of counterpart to open-source software licenses that is intended to apply to things like books, videos, photographs, and so forth. There are a variety of Creative Commons licenses worldwide (e.g. these are the choices offered on Flickr), but for our purposes here, one important distinction is between the licenses that allow commercial use and those that do not.
A noncommercial license means: "You let others copy, distribute, display, and perform your work--and derivative works based upon it--but for noncommercial purposes only."
The problem Creative Commons is trying to solve is that noncommercial turns out not to be easily defined. I've discussed this issue in more detail previously, but essentially, we operate in a world where opportunities to "microcommercialize" through Google AdSense and self-published books abound. So drawing a line--especially one that the content creator and the content user can agree on without too much thought--is hard.
See this comment from an earlier post, for example. ("Commercial" is a particularly confusing term, with respect to photography, where it refers to uses that aren't primarily editorial or artistic, and involves requirements for model releases and the like--which is only incidentally related to commercial use, as Creative Commons uses the term.)
It's not hard to see how we came to have such a noncommercial-use clause. There's a certain visceral appeal to saying, "I'll share my creative works with the world, and anyone can use them for free, so long as they credit me and don't make money off them. If they do make money, I want my cut or have the right to prohibit use."
As I say, appealing. Also not very workable or useful. A lot of truly personal and noncommercial uses are already either likely covered under Fair Use or are trivial. (Does it really matter which license the photo you downloaded to use as desktop wallpaper for your computer uses?) And prudent companies will ensure that all rights are in order by contacting the content owner directly, no matter what the license says.
I find it notable that no major open-source software license contains restrictions about who may use the software. Different licenses have more or fewer requirements about the circumstances under which you must contribute code enhancements back to the community or on actions you can't take (for example, related to patents) if you wish to retain your license. But they don't differentiate between whether you're a Fortune 500 corporation, a school, or just an individual playing around for fun.
If open-source licenses did routinely have clauses governing who could and couldn't use software, I think that it's fair to say that open-source would have had a much smaller impact on the world than it has.
As I've argued previously, by contrast, Creative Commons licensing offers up a complicated set of options that seem calculated to encourage people to contribute works to the commons while not pushing their envelope to allow any uses that they might consider "unfair" in some way. The result is a system that is far too complicated and that doesn't offer any real benefit beyond a simple license that requires 1.) attribution and 2.) downstream derivatives to maintain the same license.
Complexity, ambiguity, and lack of awareness are the issues with Creative Commons. Tweaking the signage associated with the overly complicated smorgasbord of options doesn't address any of those things.