He can't be worse than George Lucas, and Star Trek (2009) was awesome.
Special effects these days are so good, that it is a given. Especially with a Disney budget. The story, I am going to keep my expectations extremely low... like Phantom Menace levels of low. More than anything, I hope they nail the characters in the new movie. Get their dialogue right, make us care about them, and not have to cringe every time someone delivers a line. Abrams work with Chris Pine and Zach Quinto on Star Trek makes me really hopeful.