Although the movie gets a lot of flak for being 'unoriginal' at times, and not having much of a shift in technology (relying mainly on the basic X-wings/TIE fighters/Star Destroyers with some slight design tweaks, and apart from BB8 the Droids were mostly R2 and 3PO types with the "gonks") it's interesting that TFA-apart from of course Chewbacca and a few returning ROTJ characters-the alien designs were pretty much all new. While the other films introduced new aliens of course, they also tended to recycle some from the other films-A Rodian (Greedo type) shows up in ROTJ for example, wearing Greedo's exact same costume, and you can even make out some of his dialogue from the first film when R2 and 3PO show up at the palace. The head-tailed Twi-leks-famous for Jabba's right hand Bib Fortuna and the dancing girls in ROTJ-are pretty much all over Episodes I-III, and one of the chief recurring villains from those films-The Trade Federation Neimoudians-are very similar to the two squabbling green cantina aliens (Called Duros mainly). However it seems in TFA they're nowhere to be found (Although with Ewoks and Gungans, that's kind of a blessing)..
Not that it's necesarilly a bad thing. Abram's Star Trek films steered clear for the most part from the Klingons (Who were antagonists in most of the original crew films and in Generations) and Nero's Romulans were largely different from the devious schemers from the previous show. The Vulcans except for Spock were pretty much written out (Enterprise perhaps overused them a bit) Plus a lot of the new aliens-both practical and CG-were pretty well-designed and operated, with a few exceptions (Rahktars).
Should Episode 8 stick with new alien concepts, or bring back some of the older ones to give a greater sense of continuity.