I understand your concerns MEB, thanks for your post.
Firstly I want you to know that I am interested in improving the CMS as a whole for everybody that uses it, so if anyone has any suggestions or areas they feel need improving in the cms then let me know and if the improvements would likely benefit other users I'll do my best to include them. Secondly as I am an avid user of Xara myself I do plan and hope to keep the cms up to date and working with new Xara versions, websites always export in standard formats like HTML and CSS etc. so keeping the CMS up to date with it hopefully won't be too hard.
As far as installing the cms, you don't really need to know php. To install you just need to use an ftp client (I use filezilla) to upload the files. And after upload is complete a few directories need to made writable, this is all done using the ftp client aswell. That's pretty much the gist of it, you only need to use php if want to customise certain parts.
A backup of all cms content and settings can be done by simply clicking a Create Backup button and then you download the backup file to your computer. If you wanted to restore the backup, you upload the same file and click Restore Backup button. It's pretty straight forward.
I'm happy to provide support by forum and by email, the professional install option is for users that just want us to set the cms up for them as quick as possible and with least amount of fuss. But if you're thinking of using it for client websites it's probably better to get stuck in yourself anyway.