I think this nepotism stuff I'm reading is overblown. I don't see a problem with Will Smith wanting to help his son succeed. A lot of parents do and would do what Will is doing if they could.
And Jaden has done two films-Karate Kid and The Day the Earth Stood Still-without his dad co-starring. It's not like he has been propped up by his dad for his whole (short, and just beginning) career.
Do I think Jaden is the best actor ever? No. There were some parts that annoyed me, but at the same time his character was supposed to be a bit whiny and skittish. He was playing an untested and overwhelmed teen way in over his head. I'm not quite sure how else he was supposed to play that?
I don't think the accents the characters used helped make them anymore endearing to be fair, but those were decisions made way above Jaden's head.