I hate it when aliens look like slightly-recolored humans.
District 9 had aliens that were fucking ALIEN. Avatar has blue humans with slightly feline characteristics. Lame.
Viewers will complain if the aliens aren't relatable enough. Especially when writing a romance.
See, that statement bothers me.
I mean, consider this: District 9 was extremely well-received and is very popular. It also features visually revolting aliens.
Despite their OH GOD KILL IT KILL IT appearance, the audience comes to sympathize with them; the Prawn people, despite being LOL SO CRAZY AND RETARDED, are sympathized with due to the atrocities they have had to endure on Earth. Christopher is a devoted, intelligent dad who wants to save his son and his people. Even CJ, his son, has been deemed "adorable" through his adorable ACTIONS.
Avatar could have sympathetic aliens who happen to LOOK. FUCKING. ALIEN. If Cameron doesn't think he could create an alien romance with aliens that aren't hot, then he should drop the romance. Just make it a human/alien friendship or team-up instead of shoving in a laughable romance that drags down a movie. His creative bankruptcy should not destroy what should be an enjoyable, visually stunning movie.
And that's pretty much my two-cents on the issue.