It's work in progress, people should chill.
I think Evilore said it as well as anyone could.
Concept art sets the tone. It directs the imagination of the team, sits in the back of your mind when you're writing for these characters and also completes your visualization when you're eventually playing as them in low poly 3d form. It's very important. It's not there for PE in any capacity.
It's not simply people freaking out because it looks bad and they want good art just to have it, but because this type of early, normally high concept, art can have a rather broad impact on the game. People want to see high quality and most importantly inspiring concept art to not just get themselves excited about the game and what possibilities it holds, but also that it inspires the creators as well and fuels that enthusiasm and creativity down the line.
Showing this to us just does not inpsire confidence, the game probably won't suck as a result, and the end product will probably look good, but right now this is all we have and a lot of us really wish it were something better so we could believe that whatever else they've got cooking up in there is also great, but we don't, so we can't. First(ish) impressions and all that.