No, I don't think that's possible.
Thanks. Adobe take note!!!! While I was at work I worked with a Documentum database using Acrobat - and we had a brilliant feature that enabled setting the bookmark defaults.
I never realised that it had been produced 'in house' until I used 'Native' Acrobat.
You can make a feature request here: Feature Request/Bug Report Form
If you're interested, I've developed a tool that allows you to set the zoom level of all bookmarks in one or more files easily and quickly.
You can find it here: Custom-made Adobe Scripts: Batch Edit Zoom Level in Bookmarks