I have to disagree with you here. I have no problem with that because I think it should be up to the viewer to engage their own imagination and believe they are truly different. I am not going to begrudge a show simply because they don't have the budget to make every alien look truly alien to us.
I'm not just talking shows, I'm also talking games. A lot of the species don't have much thought put into them, like evolutionary origins or history. Their only role is to give the opera a sci-fi feel. They tend to look pretty human, but more importantly, they tend to act very human in order to be sympathetic characters.
I tend to prefer softer sci-fi since hard sci-fi ends up sounding too much techno babble to me. But then again I'm not really into sci-fi.
One of my beefs with sci-fi and fantasy is when they try to nonsensically insert 21st century modern culture without reason (i.e. even though fantasyland is equivalent to medieval Europe everybody believes in free love and gender equality, and the story doesn't explain why) or try too hard to be the complete opposite (dystopia for the sake of dystopia).
Also I just hate a lot of fantasy cliches. Heck I'd say because of them fantasy has less of a reputable reputation than sci-fi, though this might be starting to change slightly with the popularity of stuff like AGOT.
That's definitely one of my problems as well. Modern western morals get kinda transparently projected onto the universes. This is fine if the artists' goal is to create a pretty typical drama with social commentary, but it fails to make a believable universe. Space operas routinely involve a brave human and his/her diverse band of followers, including a lot of aliens whose main purposes are to lend a sci-fi feel to the piece and to serve as indirect but fairly obvious methods of social commentary. Sometimes they drop the second part. The moral is usually "something something tolerance." Not that I have anything against tolerance of people from other races, ethnicities, cultures, genders, etc, but as a theme in fiction it is tired as all hell. It just makes the piece seem like an after-school cartoon show. I'm a little tired of seeing mercenary/military/adventuring bands composed of people from every walk of life, even those who would never be seen doing that sort of thing. How many scantily-clad women flock to armed groups because they want to fight and show off their huge... tracts of land, anyway?
I'd like some kind of realistic game or show or something that focuses on the effects of sci-fi technology on society. Few if any aliens, limited extraterrestrial settlement, very advanced AI, an ecologically devastated world, and so on.
But maybe this is the wrong thread for all this.