I noticed that, in The Force Awakens, we see very few of the alien species we met in the other movies: there are
- no Twi'leks;
- no Rodians;
- no Transdoshans;
- no Hutts;
- no Gamorreans;
- no Ewoks;
- no Ithorians;
- none of the Mos Eisley Cantina aliens, like
- the Aqualish (spider-face),
- or Chadra-Fan (bat-person),
- or Shistavanen (wolfman),
- Devaronian (the demon),
- or Duros;
- and no representatives of many other familiar species.
As far as I could tell, the only alien species in The Force Awakens that have been seen in previous films are:
- Humans (Han, Leia etc)
- Wookiees (Chewbacca)
- Mon Calamari (Ackbar)
Whatever Nien Nunb isSullustans (Nien Nunb)
However, we see many alien species in Maz' castle, so the problem isn't simply a lack of time and space for the appearance of familiar species of aliens.