Ng is 9th on the 36ers' all time 3 point shooting percentages (39%). His ranking is largely due to 3 seasons where he shot above 40% from the 3 point line. The seasons were 2011 (42%, Clarke coaching), 2010 (46%, Ninnis coaching) and 2007 (43%, Smyth coaching).
The rest of his career, he's shot the 3 at below 36%. He's returned low and high seasonal 3 pt percentages for all 3 coaches he's played under at the 36ers. Like Hendo8888, I can only conclude it's not the game plan and coaching.
It seems to have more to do with his one dimensional game. Most of the players above him on the 3 point shooting percentages with the 36ers could create their own shots and are or were much more versatile and harder to defend - Maher, Ballinger, Pearce, McKay, Cattalini, Farley, Brooks. the other 2 were Forman and Kubank and Kubank brought outstanding defence.
So, if we have a team that will allow him to camp outside the 3 and wait for the ball to be kicked out for a set shot, then he's worth getting. If he will consistently have to work to create his own shot, then probably not. So a Schenscher at the pivot or a strong point guard who can penetrate at will (a la Ervin) would be needed.