There's simply no way to make it look good in portrait in the current version. Essentially it defaults to a two column layout with art on one side and text on the other. The next edition of InDesign will address this issue but like I said it's expensive and not exactly drag and drop. Formatting can be a real headache with InDesign.
With Author make it look good in Landscape since it's the default layout then accept the fact portrait is just for people that want to read the text in that orientation. Personally I'd rather either be able to lock it as I said or have it drop all artwork in portrait than deal with a messy layout.
It's the early days and all this will go away over the next few years. I still remember thinking what a miracle the early spell checkers were back in the day.
There's simply no way to make it look good in portrait in the current version.
I agree the tool has limits, but I'm not sure I'd go that far, sorry
As for locking...
Personally I'd rather either be able to [clip]
http://www.apple.com/feedback/ibooks-author.html - also, you may want to start your own thread on what you'd like to see, so that it can receive the unique attention it deserves, etc.
Apologies, Giglic, for side tracking the thread