You bring up some interesting points and yes it could have been worse. It does appear more a warning attack. But there are other things which don't add up because although the Yemen war is a problem for Iran, its not the problem which is crippling its economy. That is the problem of sanctions and ending the war in Yemen won't end them. Also the Saudi's can't end the sanctions just the US.
I think what I'm missing is were in the midst of a policy shift regarding the ME and the even bigger battle for the Geo Political Center? Trump is obviously adverse into going into a full scale war over this confrontation and is putting the responsibility of retaliation on the Saudi's or its anti Iranian allies. At the same time he is making it clear attacking Saudi Arabia won't result in the sanctions being lifted, it will actually do the opposite. So the US may support the Saudi's in a retaliation or war with Iran but not become involved in the actual fighting?
This may make the chance of war more likely since I believe the US has been instrumental in controlling the actions of some anti Iranian states such as Saudi Arabia,UAE,Israel and Egypt. If these nations ally against Iran it would be a formidable force and Iran would not prevail. It could also be a much dirtier,costlier and longer war with higher casualties?