What would be the advantage of starting a distribution from scratch?

On the negative side I see that meego will loose on some areas:

1) The amount of knowledge that can be harvested from the existing forums,wikis. Using, let's say, distribution X as starting point, one can figure out what to do to fix or adapt things in a new derived distribution.

2) Tested and packaged software (specially, ARMel and all others that are not x86 compatible). yes, sometimes you must recompile and repackage, but it is easier when there is already a working software that expects more or less the same libraries to work.

3) As it was already pointed out on the dev-list at meego, if a new distribution follows closely the structure of a base one, it makes it easier to just use prepackaged software as much as possible. It might be the case of automatically rebuilding common packages, for instance. Now, since it is a new distribution, it will be harder to do that, because things will probably be placed on different places with different configuration options and so on.