I love the idea of treating output as tabular data.

I see you already have a where operator. What would fit this very well would be in-built sql-like syntax. Since tables are first class, you should have an in-built way of handling them.

A languiage similar to q/kdb - it has a great SQL dsl, but also works as a regular programming language. It's also very concise and expressive, you can write oneliners that do mind bogglingly complex things.