The only similar show out, Battlestar Galacitica survives by being tight, edgy, having no aliens, and aiming for a good sense of reality all around.
I also see the little-or-no-aliens aspect to be the going trend now. Battlestar Galactica has only humans and Cylons, and even the Cylons look human (not only a budgetary advantage but an actual part of the story). Stargate: SG1 occasionally has non-human aliens, but usually the people from other planets are just transplanted humans, or in the case of the Goa'uld, human bodies hosting symbiotes that we rarely see. Stargate: Atlantis has the Wraith, but it's been implied they may be human/bug hybrids (DNA altered by the species of bug that once attached to John Sheppard).
On the big screen, Lucas uses aliens for Star Wars, but his stories garner a lot of criticism from both critics and fans, and his main characters are still usually human.
I actually like the idea of different alien species/races, even if they look semi-human due to the unavoidable reality of being played by human actors. I like the different cultures, the different perspectives, etc. But, I'm afraid the days of alien cultures seem to be getting old fashioned.
In the past couple decades, only JMS, Roddenberry, the Roddenberry beneficiaries, and a couple others seem to have ventured into the realm of alien-based shows. Out of those, only B5, TNG, DS9, and--unfortunately--Voyager, have been successful. Crusade had the imfamous corporate problems. Enterprise, Earth: Final Conflict, and Andromeda all suffered from bizarre story directions and--as a compounding result--lack of enthusiasm. Unfortunately, Alien Nation never did take off very well either, and even it only had the one alien race.
The 70's through 90's were the age of aliens, but the 2000's seem to be the age of the human. That's not necessarily a bad thing if writing and performances are still good, but weren't Cardassians, Centauri, Klingons, Minbari, Narn, Romulans, Tenctonese, Vorlons, and Vulcans a lot of fun while they lasted? Hopefully, the Star Wars TV show will make the best of Wookies and Yoda's people so that aliens can get back in style again.