Something is surely needed, because many of the icons are non-descript enough that you need the mouseover text to know what they are represent. Yet the mouseover text doubles the space taken by the launcher, which slows the use of the launcher and partly defeats its positioning.
Problems like these are easy to correct, so the question is why they were left for the official release. As things are, Ubuntu Netbook sometimes leaves the impression that its components were developed individually, without enough overall coordination.
Ubuntu Netbook is not alone in its assumptions or inconsistencies. All the netbook desktops I have seen have similar problems to a greater or less degree, although Plasma Netbook is the closest to being exempt, since it amounts to a skin over the KDE code that you can swap out if you choose.
Part of the problem, I suspect, is the time between a project's proposal and delivery, even in free software. In the case of netbooks, design assumptions were made at a time when netbooks were underpowered and developers could only guess how they would be used. Now, netbooks are more efficient, and the guesses about use cases seem partly incorrect, but these changes have still to show up in planning.
Another part of the problem is that usability experts as a whole -- and not just in free software -- tend to mistake simplicity and over-simplification. Not only can you simplify without ignoring use cases, but you probably should, because otherwise, users will continually find ways to use your software that will surprise you.
In theory, a netbook desktop should be possible that does not constrain users to a single way of doing things. Unfortunately, in practice, the latest version of Ubuntu Netbook is not that desktop.
ALSO SEE: Why Does Everyone Hate Ubuntu?