As a former air force transport crew member (C-141A) I share the emotional preference for four engines over two. Compared to WWII vintage transports, the C-141A had superb engines - power and reliability. I don't need five fingers to count the engine shutdowns I have experienced with thousands of flight hours in 22 years.
As an engineer, but not a propulsion expert, I know there is a large body of mandatory standards, measurement criteria and demonstrations required to determine ETOPS approval. Every time a new airplane or a new engine fit is evaluated on transport airplanes, the ETOPS process receives a great deal of attention, as it should. This system has proven itself I believe, and to the degree that it is faithfully followed, with the integrity and professionalism expected of test pilots and engineers, we can trust it for ETOPS 180 and even for ETOPS 330.
Human nature, being what we know it to be, can lead to shortcuts, deviations from process, pencil-whipping and the like. Just as hazardous for ETOPS 180, though, as it would be for ETOPS 330.
Once the airplane is certified and delivered, the operator (airline), its management, flight operations, maintenance, and so forth take on the responsibility for following a very strict set of mandated requirements. to the degree that those charged with these responsibilities carry them out responsibly, we can trust ETOPS, whether for 180 minutes for 330.
We know HOW, we know the technology and the engineering. It only remains to DO the job responsibly.