(Quote from Terry Pratchett's book Thud)
Personally there are quite a few things that I would change, and this isn't much of a rant as I'm suggesting improvements other than just getting angry at the problems.
1. This OS is Anonymous.
People normally haven't' heard of Linux in any way, shape or form. They don't knew anything and as they haven't tried it don't want to change from Windows. We need to show them it, but not force it upon them as they will just say no.
People forget about the other Distributions or haven't heard about them. This means when Ubuntu does something they don't like, then they move away from Linux altogether.
Why don't some things work? Yes I know that there are teams of people around the world who are making open source versions of the drivers, and that some companies do provide them or don;t bother, but when I plug my printer in, or connect an iPod, or use Wi-fi, I want it to work, at least when installed with no further messing around on some distros (as some are not willing to put in propriety code which is fine by me), if not on the Live disc. Many people have tried to use Mint on their laptop live and not been able to connect to their Wi-fi. I have also had this problem with our printer, an Epson Stylus DX6000. On our dual-boot box, Windows works fine with it, Ubuntu used to until we got rid of it, and so did Mint, but now Mint 9 has a big problem with it. After a while, the OS claims that the printer is not connected, and won't let you print until you turn both the printer and the computer off and reboot. But, on my PC, with mint 10, it has always worked perfectly, right from mint 6. Both Linuxes have to use the DX4850 driver as there isn't a native one, but the CUPS on Mint 9 (LTS) is broken now after an update.
4. The geek factor
Those who do know Linux, but haven't tried Ubuntu, know it as a platform for geeks, with flashing green text, and no graphical desktop, or broken messes of a desktop. But, what they don't realise, is that in 10 years, Linux has gone from being a pet OS to being capable for general desktop use. In most cases. There are still times when things mess up and it's either really tiny niggles, or something massive, like X not working. This is mainly because it is all done by volunteers in their spared time. It's a community effort and some people don't always understand that.
5. Desktop Themes and Title Bar Layout
Ubuntu is now famous for changing the Minimise, Maximise and Close buttons to the left, Mac OSX style. They have the freedom to do that, but maybe it would be best, for such a famous distro to put it as a non-default theme rather than the default. Also, some of the themes for distros aren't really that nice and are outdated. Ubuntu, Mint, Suse (KDE) have nice themes but some of the others really need to make their desktop more attractive and east-to-use. Minimalistic distros can keep their style as they look nice, but Kubuntu, Fedora, Debian could make their desktops nicer, even if it means adding it on as an optional extra.*
There's more, but I really can't be bothered to add it. The list isn't exhaustive. This post would be bigger than 1 page!
*Since I wrote this, Fedora has used the new Gnoem3 Desktop as their default and it looks swish. Yes, it means there is GNome2, Unity and GNome3, but it means that each distro has some difference, rather than the wallpaper and package manager (Package Managers...Why!)