Looking at the fact that China doesn't have any experience with the developement, building and maintaining steam catapults, it doesn't really make sense to invest money, manpower and know-how into such a project and don't just plain move to EMAL, even if EMAL is the more complex solution.
Well, that how a bunch of engineers would handle it. But you don't know what happens when non engineers and even politicians are involved.
I wouldn't say EMALS is necessarily the more complex solution than the steam catapult solution. In fact, the opposite might well be true. The US has long history of constructing, operating and maintaining steam catapults, but China is new to both solutions. And there is not much overlap in technologies underlying either solutions.
At this point, it really comes to down to the relative maturity of the two solutions under developments in China. It has been believed that steam catapult is ready or close to ready. EMALS wasn't even on the radar screen until a few years ago when Rear Admiral Ma Weimin built a 1:1 prototype (shortly after 2008 I believe) through his own funding channel and has won all kinds of acclaims since then, including from the two successive presidents Hu Jintao and Xi Jinping. It appears that more progress has been made such that now EMALS has become a serious contender for 002 and/or beyond.
I don't think politics necessarily has played a role in delaying or accelerating EMALS' development or inclusion as candidate solution, as some seem to believe. Carrier program is a high-profile, high-risk program for China; the leadership could not afford to take too much risks. It was Ma and his team that have "forced" their way into the picture.
