It depends on who you believe. Both Su and Deng said they were the leaders. Deng had tendency to exaggerate. For example Deng told people that he attended Zhun Yi meeting but it could not be verified. He lied many times in history.
People knew Su was the leader just as Lin was. The misunderstanding seems started in recent years. Before 1990, people would agree Su was the leader. But Chinese history advances over time.
Anyway, Chinese were killed a lot in that war. And poor people were still poor after many years. If a Japaness learned that you think there were heros in that war he would think Chinese are not smart. But go ahead enjoy yourselves.