Well, there are always little things...jokes to make about what the aliens don't understand about Earth culture, and vice versa...and of course, the introduction of hyper-advanced technology that can really only come from aliens or people from the future. There are certain niches in sci-fi that aliens fill simply by being aliens, no matter what they look like.
I didn't really mean simpler as in 'more convenient, less effort', I meant simpler as in 'less confusing, less likely to alienate readers entirely' (pun intended). It's not impossible for people to get invested in things they don't understand, but it's a risky gamble, and one that most amateur writers don't want to take.
Like...no one is speculating that deeply about my work. No one is going to make the effort to translate my original alien script. No one cares that much, at least not yet. It's painful, but it's the truth. =/ So as fun as it might be to throw in a whole bunch of mysterious stuff, in the end it all has to take a backseat to the things people will actually be able to comprehend.
I don't think people who make humanoid aliens always do it out of laziness. I think they just do it because maybe they don't feel like wasting creativity and effort on something super-outlandish that no one will realistically make an effort to understand. Me, I have creativity to spare, so I don't care. But not everyone has that luxury...