I was thinking about this, as the US is trying to get a 3-way deal that involves Saudis-Israel having talks, a path to a Palestinian State and some stuff for the US. Maybe this person wouldn't be down with this plan.
Iran is a major enemy of all three of USA, Saudi, and Israel, so why would Iran's president have anything to say about that?
If this incident has any foreign involvement (which I doubt, considering weather conditions), then the first motive I'd assume is simple revenge/punishment rather than any specific strategic aim. It's hard to imagine whoever replaces this guy being in a position to be "softer" on Iran's enemies immediately after one of Iran's enemies was killed.