If you consider only or predominantly his portrayal in LOCH, Wong Yerk See's designation as "East Heretic" is well-merited. Based on LOCH, he clearly wasn't a very normal or nice guy: crippling his own students and often tormenting his enemies in sadistic ways.
If you consider only his appearances in ROCH, however, "East Heretic" seems more like "East Hero." Though still an oddball, Wong Yerk See did something heroic in nearly every one of his limited appearances in ROCH. He saved at least one life each time he appeared in ROCH: Ching Ying in his first, brief appearance at the beginning of the story, Yeung Gor, Luk Mo Seung, Ching Ying, and Sor Goo when he showed up again later to save them from Lee Mok Sau, Gwok Fu at the Heroes' Conference at Seung Yeung Fortress sixteen years later, Gwok Seung from the Golden Wheel Monk at Passionless Valley, and of course de facto leader of the heroes and defenders during the final battle of Seung Yeung. In fact, at the points when the heroes got into fixes...the problems at the first Heroes Conference at Luk Family Manor, Yeung Gor and Little Dragon Girl's struggles at Passionless Valley, Gwok Jing getting ambushed by the Golden Wheel Monk and Mongol warriors at Kublai's base camp...none of it would have happened if Wong Yerk See had been present. Indeed, Jin Yong seemed to consciously limit Wong Yerk See's presence in ROCH because he would have turned the tide in the heroes' favor at several critical junctures.