Following on from how Gnome is no longer fun, I thought I'd give my perspective, as a person who dropped out of mainstream Gnome-ness to just get on with what I found fun.
I think there are a number of reasons to why Gnome is "no fun" anymore. Other people have brought some of them up already, and seeing as I'm making this up as I go along, I'll probably be retreading the same ground often, but what the hey...
The Lie of Open Source Projects
There is an underlying assumption that an open source project must be as inclusive/transparent as possible. From this, it is thought that all mailing lists must be open, all work must be done in public, all interactions must be seen by everyone, and that all participants in the project are equal. I think this is a lie.
There are many people "involved" in the project, from the coders and designers, to the documenters, translators and testers, and even down to the lurkers on the mailing lists. The lie says that these people are all equal, and that all input, no matter where it comes from, is valid. The problem is that often (not always, but I'll come to that later) it is not. While translators and documenters and testers are all nice people to have on a project, and that it is true that a project may not be complete without them, they are not essential to a projects existence. People will use a program that meets their needs whether it is documented or translated into their native language or not. Programs don't even need to be well designed for them to be popular, they just need to meet the users needs at that time. (eg: winamp and a million other programs) The only people who are essential to whether a project lives or dies are the people coding it. Without sniggering take the doomed GoneME fork of Gnome...a million (well, okay, 10) people with a million ideas, but not one of them with any clue how to put these ideas into code.
No programmers = No project
And this is the first problem this lie perpetuates: Everyone on a mailing list thinks their view is just as important as the people who are doing the work, and the people doing the work end up having draining and 99% of the time pointless flamewars justifying their actions as though they were accountable to the hangers on who, generally, are not very polite about things. Every minor (or not so minor) change in a UI layout apparently renders the entire program USELESSS!!!!
The second problem that comes from this lie is that it helps create and sustain a tabloid press (OSNews, you know who you are). All dirty laundry is washed in public and every little detail is hailed as important, when in fact, its really not.
Both of these problems mean that the coders are being forced to check and double check their work, and anticipate every little detail that might offend, annoy or antagonise the user/reviewer/tabloid journalist or render the software USELESSSSS!!!! This can zap the will of people to do anything, because there's always someone who will be annoyed or at least make out that they will.
If everything is slammed or scrutinised by people who don't matter, it not only destroys the people codings productivity, but it has a detrimental effect of also scaring off potential contributers as well, who look and see this scary bunch of people who just scream USELSSS!!!!! at everything. This whole situation arose from Edd's comments, and although he didn't mention it I think he's feeling the effects of his Bluetooth stuff being dissed and slammed by people who didn't even understand the things they were talking about (Edd, if you read this and I'm wrong, let me know and I'll remove this bit)
I don't know really, but I'd suggest closing Gnome down slightly, raising the barrier of entry, so that people who contribute nothing are prevented from distracting the people who actually matter.
People will obviously complain about the gnome elitists, but from my understanding Firefox is an invite only project and it clearly hasn't hampered it.
I think the fun element will return when people are allowed to do what they want to do, without having to worry about the vast majority of people who don't matter.
I program for myself, if other people like what I do, thats nice, but its not what I do it for, so so long as I like what I've done, then I'm happy.
(and before anyone complains that I'm relegating everyone who is not a coder to a lower status I happily admit that there are non coders to whom many projects would not be in the state they are today and whose contributions to the projects are of immense importance, but these people are few and far between, and it takes a lot more work for them to contribute just as well as coders. So for you guys, I applaud you)