Like previous Amiga models made possible emulation of DOS and Mac OS, it should optionally run Windows and OS X, to start, maybe as virtual machines, and because of superior Amiga architecture, offer a performance boost.
As an Amiga, naturally, it should deliver graphics and sound to make other systems seem like stupid, sad joke-boxes. It should be positioned where Amiga was initially in the market, compared to the other boxes, offering that amazing competitive price-performance value.
I'd like it to be ultra-portable, bundled with high-resolution LCD specs and instead of a mouse or keyboard interface, it would have light-weight gloves with fingertip-sensors that let me type, touch and manipulate virtual 3-D objects and instruments in a natural-media way and feel. Or maybe it would see my hands without a glove interface.