The reason why it was not done this way originally was to allow for separate releases of these projects. I guess your just talking about simplifying the situation where you want to pull down all the projects together as a group. That sounds fine.
Yes, it's just for convenience. You would still have a trunk folder for each subproject, and you can still do separate releases. I'll just add an additional "trunks" folder that contains a link to each of the trunks.
I noticed that this is how the maven svn repository is setup, and it seemed like a nice idea.
I noticed that the trunks folder does not work when accessing svn through the anonymous URL because the aliases are all pointing to the https url.
Do we need to have a separate anonymous URL? I've set up subversion in the past where read access is anonymous, but when you try to commit, you are prompted for a password. This way you can have both types of access without 2 URLs.
Talk to it about why it was setup the way it was. I don't know if bandwidth was a concern.
Sounds like svn needs a replication tool that allows for link url rewritting.