There's a huge gap in Java build tool space for a tool that is simple and easy to learn and can cover 90% of projects' requirements. I have this feeling that we're in the "subversion" days of java build tools and the day someone introduces "git" people will wonder why we suffered with Gradle and Maven for so long. If I had time I would be looking into building this.

predating Gradle was a tool called gant. It was simple, intuitive and did 90% of what every project could want. Ironically it was Groovy based as well. But instead of the Gradle arcane magic based configuration it was literal, direct, a simple extension of Ant that came before it. I liked it much better, but someone decided they could make a business out of Gradle and gant got deprecated and here we are.