Just as the title says, I think Alien Sims should have something to do.
All the other occult sims, besides mermaids, have aspiration paths. But with the mermaid pack, you at least get Sulani and there’s a lot of stuff to do there; in addition mermaids have slightly different needs and animations. I wouldn’t mind a Mermaid aspiration path but that’s for another discussion.
For now, let’s focus on Alien Sims. Besides having a human disguise and alien form, there isn’t much appeal to making one. They can Empathize and Detect Personality with Sims, along with some other curious interactions; but that’s about it.
This leaves virtually nothing different from playing a human Sim besides the fact that they can’t tan. You don’t need to be an alien to go to Sixam, you don’t have special interactions with other aliens, no special moodlets from eating alien fruits, the only thing that differentiates is the embarrassed moodlet when a sim finds out you’re an alien which affects almost nothing.
Indeed, this leaves you with an incredibly similar experience to playing a human, as even the needs are the same. Having two forms does give you an opportunity to make a lot of different outfits for them but you can do that with a human also.
To improve the gameplay experience for Alien Sims, I would suggest some new actions in the interaction menu, some altered needs, quirks, and skill tree and aspirations; similar to the Vampire or Spellcaster skills, you have to do various things to gain experience points and level up to gain different abilities.
Off the top of my head, I think it would be cool to have a “Beam Me Up” sorta skill, where you can call a UFO to beam up the sim and drop them off somewhere; like how Vampires, Werewolves, and Spellcasters can fast travel with their respective abilities.
With the aspiration path(s) I think there should be one where your Alien Sim has to study humans so they can blend in more effectively, and the reward trait makes it so you rarely get discovered as an Alien or something like that.
To study humans you can abduct humans (like how it can happen to you), cows (classic), and many other things. You can learn human culture by watching TV, listening to music, etc. The less “human knowledge” your Alien Sim has the more weird stuff they should do: wearing clothes backwards, sitting in chairs the wrong way, etc.
I could come up with some other stuff but I wanna see what y’all think.