I've also been frustrated when testing out tools that kinda keep you locked into one predetermined view, table, or set of tables at a time. I made a semantic data modeling library that puts together queries (and of course joins) for you as it uses a drill-across querying technique, and can also join data across different data sources in a secondary execution layer.

https://github.com/totalhack/zillion

Disclaimer: this project is currently a one man show, though I use it in production at my own company.