Way I'm reading the articles is that the ruling is way to open to consider this a victory for Trump,which is why it was mostly send back to the lower courts and told them what we already knew, that the Presidential acts are by themselves not punishable.
Obama killin a American citizen abroad was done as a President, Obama as a canidate didn't benefit anymore then any other presidential act he could carry out.
Obama killing Mit Ronmey however would be zero benefit for him as President and would be considered in my opinion only a benefit for Canidate Obama so not a official act.
If Trump wins however he will probably consider himself to be god king or something, because from his pov that is what the SC told him even if that wasn't the case.