I agree that this is a matter of statistics. It seems to me intuitively that 2 incidents in 3 weeks where an aeroplane lost 50% of its thrust on an Atlantic ETOPS aircraft is rather high.
Your looking at an irrelevant statistic. Just becuase 2 aircraft had engine failures is not relevant. You need to look at what types of engines were on the airplanes. If they were the same model of engine then you may have a point. I'm guessing the Delta plane was a 767 or 757 and thus a completely different engine than a CAL 777.
Also unless there is a common reason for the failure/shutdown of 2 engines of the same model, there isn't a reason to worry.