I feel there should be a Liberated Borg Alien character creation for this game. Even if it's something that you would have to purchase from the c-store or for lifetime members. The fact that your scripted to be either a Human, Klingon, or Romulan Borg liberated isn't that appealing. I feel this would also make the most sense for a story of a character the reason they are here is they got liberated from the Borg and that's why you have never seen there species before.
On a side not I would also like to see Hirogen added to as a main build for a charcter as well with their armor and mouth piece I think they would work great for a character in the new Romulan legacy release. They would make a good faction side character for the Romulans to ally/use with.
You can create a decent enough Liberated Borg Alien character as long as your character is Federation and Female. Get the 7 of 9 costume set and use the infected skin. However, your implants are just limited to the 7 of 9 implants and your character is Borg in appearance only.
Actual Liberated Borg Alien characters should be limited to just lifetime members. As long as Romulan characters are forced into the Romulan Republic, then I don't see Hirogen happening since they are allies of Emperor Sela and their hunting practices are likely shunned by the Romulan Republic so it would require Hirogen that betray their entire culture.