The great Great-Room Craze of the 1980s was all about openness: Why should the kitchen be so removed from the other living spaces? Indeed, why should there be any distinction between one public room living, dining, den and so on) and another? Everyone should happily congregate in one free-flowing space.
Sadly, the result is usually a great big mess. Think about it:
The Echo Chamber You know what you get when cooking, video-game playing, conversation and television viewing occur in the same space? Noise. Lots of noise.
Weird Windows All these windows and doorways are on the ground level and...also floating up on the second-story space, somehow reminiscent of a burned-out building. Also, how do you light such a space without it looking like a lobby in a Marriott?
An Inconvenient Truth Boiling in the summer (all that glass!) and freezing in the winter (all those high ceilings!), giant rooms such as these are nearly impossible to heat and cool without spending some dough on an engineer - and you know that's not cheap.