My favourite aspect of the G3 is the antenna that is tucked away at the top, such a simple proven piece of tech that would help SO MUCH where there is awful reception e.g where I live It's great how it is tucked away and everyone is none the wiser until you whip it out and time warp back to the 90s wooo!!
Having a clean aesthetic and some kind of modularity such as removable hard drive cages and different options of fans. Also having decent removable fan filters or at least filters on the intakes are great to have, makes maintenance much easier, I have a Fractal Midi and its great!