Preempting God

According to open theist William Hasker:

If we really, seriously believed that God would prevent any evil that did not have a greater good as its result, this would significantly undermine our own motivation to prevent or mitigate such evils. If I prevent some serious evil from occurring, I will actually prevent the greater good that, absent my interference, God would have brought about as a result of the evil in question. If, on the contrary, the evil would have no such good result, then God will not permit it, regardless of what I do or don't do. The failsafe option, then, is to do nothing, C. Meister & J. Dew, eds. God and the Problem of Evil: Five Views (IVP 2017), 160.

i) I don't think God permits evil only for the sake of greater goods. An alternate good will suffice.

ii) If I was a consistent open theist, I'd be more risk-averse. On that view, God is less likely to override the laws of nature or override the freedom of perpetrators. So why should I stick my neck out? The world of open theism is sufficiently hazardous, sufficiently random, without me further endangering myself for the sake of others. 

iii) I don't see how Hasker's alternative solves the problem he poses. If an open theist prevents, or endeavors to prevent, an evil that God would otherwise permit, then isn't the open theist acting as though he's wiser or better than God?

iv) From a predestinarian standpoint, if I intervene to prevent an evil, then that didn't frustrate God's plan. To the contrary, God intended me to intervene in that situation. God intended the consequences of my intervention. God intended the goods that flow from my intervention. So there's no tension. No need to second-guess my actions.