Why make something that already exists and is useful? Why change for something that no has usability?
It sounds harsh but the original remit was the cut down the number of icons and standardise the way they work. There's little consideration for what these icons need to accomplish or how people use them.
The process was very transparent but the conclusions drawn (that tooltips are bad, that similar things should be clustered, that things should all operate in exactly the same way) haven't helped usability or design in the short-medium term.
Jorge's blog post from earlier in the year hailed these positives but I'll post under them what I think has actually happened as a result.
More accessability, and note how he’s scrubbing through the menus with his keyboard.
But less accessibility where most people want it. The music menu is agnostic so there is (or at least was - I haven't used IA in some months) no way to quickly skip tracks with a roll of the mouse wheel. The messaging menu is compacted so there's no way to toggle the to-tray effect of single applications with one click. There aren't any tooltips so it's harder to find out what the current song or current volume or current network or who has sent you a message. It's less accessible through lower function.
I think this alone highlights the biggest issue when you try to standardise things. Each NA icon is supposed to control different applications and each of those works in a different way. Imposing a very restrictive set of design rules might make it look pretty (even that's debatable - my eyes have cones as well as rods, please use them!) but it means you have to invent a new way to control the application through its icon. So far all these alternative methods appear to be somewhat less intuitive or accessible than their predecessors.
There's also no consideration for people who don't want things clustered. I for example have oodles (3840px) of horizontal panel space. Clustering applications together just makes it even harder for me to get atomic control over something and doesn't have any positive impact. I'm sure others with less horizontal space would like to disable certain clusters.
For third party applications of the world this means they can support one “linux” thing.
Not at all. Not even for application only targeting Ubuntu. Some users (raises a hand) really dislike IA so remove it. Not all supported versions of Ubuntu run IA. Other distributions aren't picking up IA with the same enthusiasm.
In short, application developers need to do more work now than they did before. Even more so if Ubuntu does drop the Notification Area (if it hasn't already).
Everything behaves the same in both desktops and everything is consistent.
Apart from when you use an application where IA isn't targeted. Then you have IA and NA looking different, working different and the effect is about fourteen miles worse than just using NA.
My tray doesn’t feel like a back alley.
I won't repeat everything from the first point but it now feels like an incapable section that is practically only good for indicating things. There's an illusion of control but it's overshadowed by too many clicks and a lack of tooltip-driven feedback.
I honestly think that Microsoft did it right in Windows XP. Show whatever's running and wants to show an icon but hide things that you never use.
That said, there are things that could improve how IA works. The major one being to use hover instead of click for selecting IA icon. That would reduce the need for tooltips and bring things back to single-click status. And if they do want to take over the world with it, they need to replace NA completely. The only way to do that is to take the same interface as NA does and support all the applications that NA currently provides.
I wrote a post a while back documenting the regressions like this in 10.04. I have a bad feeling that within the next six months there's going to be a similar post about Unity which (unless it shows some unrealistically huge improvements soon) is just going to destroy the desktop experience.