That was a hell of a workout for you guys.
It doesn't seem fair. After Earth wasn't supposed to be your movie. It was supposed to be Jaden Smith's leading-lad coming out party, conceived, produced, and starring his leading-man dad, Will. But as soon as Jaden delivered his first lines as Kitai, a wannabe warrior living in a distant future, you must have realized how much his performance would rely on you.
Answer: a lot.
It's not that your co-stars didn't have the chance to prove themselves. In the interminably long opening monologue, Jaden's vocal chords do their best to explain what we (apparently) need to know: thousands of years ago humans were forced to leave Earth after ravaging the environment and leaving the planet uninhabitable; they found a pristine world dubbed Nova Prime where it was safe to rebuild civilization and thrive.
Or not. An alien race called the S'krell have similar plans for Nova Prime, and a vicious war ensues in which they unleash upon humanity an army of warriors that are able to sense their prey's fear. Fortunately, superdad Cypher (Will Smith) is able to suppress his fear, becoming invisible to his enemies and something, something, something human victory is secured!
(Was it exhausting to read that? Just imagine how exhausting it is to watch.)
Jaden's poor larynx must have been pretty decimated after delivering all that exposition in the film's first ten minutes, because, for the rest of the film, you two are forced to be the outer space-Karate Kid's primary method of expressing emotion. The onus fell on you, the suborbital ridge, to do the heavy lifting.
And that's a lot of lifting. In the absence of help from any other limbs or organs, you heroically stepped up to convey young Kitai's inner turmoil. Lowering to demonstrate his disappointment at not passing his space-ranger exams; frowning to express frustration that his dad isn't as much a part of his life as he'd like; arching to illustrate the joy of accompanying his father on a training mission; lifting high to communicate the horror he feels when that mission, of course, goes terribly wrong.
But you are only capable of so much. The corrugator supercilii muscle only moves in two directions, after all. Jaden Smith's crinkled brow achieves little more than expressing the general notion that he has feelings. You know, that look teenage boys use to convince girls that they're different than the other guys.
Or we could just blame After Earth's half-baked plotting for those shortcomings of emotion. With angry baboon rampages, giant bird attacks, and paralytic leech incursions, I don't blame Will Smith's face for retracting into a sour scowl and erasing every ounce of his natural charisma. Maybe it was a conscious choice. Maybe he wanted to place the focus on young Jaden. Sadly, however, the famed Smith charisma seems to be a recessive gene.
Still, I'm glad you guys brought your A-game. No one else did.