Hi Robert,
I don't think there is anything wrong with SAP's logic at all because not all company would have this similar scenario. Since this is a "standard" Budget vs Cost accounting report some of the options or parameters that you want might not be available. That's why SAP has provided a reporting tool which you can use to create a customized report that will suit your specific needs.
We did encounter a similar scenario which we ended up having to create a customized Budget vs Cost Accounting report using Crystal Reports which shows all Nominals regardless if there is a budget set or not.
Since this is more of a feature request as what Gordon suggested you can post your idea at SAP's Idea place
Hope this helps
Regards
JP