Patrick, I beg to differ with you. I think there should be fewer Linux distros out there, not more. The more distros there are, the more fragmented the community becomes, and the more duplication of effort ensues. Think of it: each distro has it's own separate website, documentation, mirrors, repositories, bug database, etc. And it takes a huge amount of manpower to maintain those all properly.
There's a very finite amount of volunteer labour available in the Open Source world, and if it gets too "watered down", then overall stability will drastically suffer, as experienced by the end user. QA ("Quality Assurance") volunteer labour, is especially precious (particularly those who actually fix software bugs).
Want proof? Witness how Ubuntu, the currently most popular linux distro ever, had a terribly unstable latest release (where 26% of polled users experienced "upgrades that failed big time", and "had to reinstall"), despite having over 20,000,000 users (at least that's the claim). If the Open Source World doesn't learn to "stand together," I feel it's future will be dubious indeed.
No doubt I will get roasted for saying this, but I feel that the Open Source world would progress in huge leaps and bounds if all the lone-wolf hackers out there would checkity-check their egos and admit to themselves that they are probably not going to be the next Linus Torvalds, and instead contribute their volunteer efforts to already-existing, well organized, reputable Open Source development and support communities. You know, "working as a team".
The existing popular distros (such as Debian and Fedora) provide well-thought-out means to have nicely organized, ummm, "sub-projects," while avoiding said fragmentation of effort. Check out Debian's concept of "Tasks", and in the Fedora world, you can make a "Remix". The Raspberry Pi community would do well to learn more about these organizational structures, and make use of them. There will be an initial learning curve to get over, but they will save lots of volunteer labour in the longer term.
For example, I, for one, would love to see, in the future, a Debian "task" package called, say, "raspi-edu-programming-python", which, when installed, would automagically install all packages developed by the Raspberry Pi community, pertaining to the teaching of programming in Python.
In summary, I feel we don't need whole new distros, we just need all the newly developed RPi-relevant software packaged properly (into .deb or .rpm, being eventually accepted into the official respective software repositories), and then using "task" packages to easily install coherent groupings of them (or the equivalents thereof in the Fedora world).
In summary, when it comes to keeping the enormous, tangled mess of open source software organized, it's all about package management, not forking a new distro. Witness, for example, how Debian already pulls off the mind boggling feat of keeping over 30,000 software packages well organized. It would be a shame to duplicate such efforts again.