I voted against. So what use is to have a ext3 MyDocs partition? Most people are already storing their documents in FAT32 USB drives already. I don't need symlinks nor fancy features to store my documents, and in fact it is mounted noexec for a reason.
Also, $HOME is already ext3.

Don't think that making it ext3 will instantly remove the 2GiB limit in /opt and $HOME. Do you want them unmounted when connected through USB?

And I can't see what are the benefits of having a 25GiB FAT32 loop file in a 27GiB ext3 partition instead of a 25GiB FAT32 partition and a 2GiB ext3 partition. Before you say "dynamically resizable!" consider that for me the only difference is that with the loop file method I won't have to use e2resizefs (but I'll have to use a tool to resize the FAT32 filesystem either way).

This is not such a simple issue.

Of course, if you don't care about windows or exporting through USB.... but that's not the common use case here. Still, I agree it has to be possible to do this on your own device.