They want an OS that's smarter about power management and easier to maintain. They describe their high-level objectives in their FAQ:
Why is a new operating system necessary?
...The design requirements of today's devices have drastically evolved in areas of power management, security, serviceability, and virtualization... By starting from a clean slate, Minoca OS is able to incorporate those core tenets into the very fabric of the operating system...
How is Minoca OS different from other operating systems?
...One of the most noticeable differences at the kernel level is the uniform driver model, which provides a maintainable interface between the kernel core and device drivers... Another very noticeable difference is our strong emphasis on the kernel development environment. Being able to step through code in the kernel, boot environment, and even firmware was something we felt was critical to quickly developing and maintaining kernel-quality code...
Why is a new operating system necessary?
...The design requirements of today's devices have drastically evolved in areas of power management, security, serviceability, and virtualization... By starting from a clean slate, Minoca OS is able to incorporate those core tenets into the very fabric of the operating system...
How is Minoca OS different from other operating systems?
...One of the most noticeable differences at the kernel level is the uniform driver model, which provides a maintainable interface between the kernel core and device drivers... Another very noticeable difference is our strong emphasis on the kernel development environment. Being able to step through code in the kernel, boot environment, and even firmware was something we felt was critical to quickly developing and maintaining kernel-quality code...
http://www.minocacorp.com/support/faq/