Much of the dislike of Unity seems more political than functional. The new environment was a top priority for Canonical and Ubuntu, and many resented the reluctance to explain the reasons for design designs, and the perceived lack of community input.
Outside of Canonical employees and long-time Ubuntu enthusiasts, praise for Unity seems muted. Some seem to be waiting to see how Unity develops before making up their minds about it. Others seem indifferent to it, so long as they can launch their applications with a minimum of effort.
When users do praise Unity, they usually mention its simplicity. Some also like the fact that configuration tools are not immediately obvious, since most users only use them immediately after installing. In many ways, Unity seems to have managed the reduction of clutter to which GNOME 3 aspired but fell short of.
With the Linux desktop pulling in all these directions at once, a return to the days when one desktop fit every need seems unlikely. The days are probably gone forever when one environment was only a minor variant of the others.
In some ways, this state of affairs seems wasteful. With different priorities, desktops cannot cooperate as easily as they once did, and duplication of effort seems inevitable. Some might argue, too, that the increased number of choices will only confuse new users.
Still, the fragmentation has its points. A project with clearly defined goals may be able to satisfy users more than an environment that tries to be all things to all people. Also, for long-time users, the increased recognition of minor projects seems long overdue.
Even more importantly, the user revolts that created the fragmentation may, in the long term, teach free software developers to start paying attention to users. Except in the case of Unity, developers looking at the last year may come to appreciate that they have no authority to impose changes on their user base. If they try, someone else is likely to come along with an innovation like the Mint GNOME Shell Extensions and give users what they want.
In the end, the fragmentation on the desktop may not be completely ideal. Yet, when you consider the individualism that is such a core value in the community, it is hard to imagine events happening in any other way.
At any rate, no matter what its advantages or disadvantages, fragmentation has become the norm on the desktop. Like it or not, at the start of 2012, it is the new reality, and shows no signs of going away.