I would suggest Shannon (EINN) to JFK would be a better ETOPS route. You need to have divert fuel etc when you reach your destination so the route you have would not be suitable unless a fuel stop was planned in Canada en route. Google ETOPs operation and you will find some good information regarding procedure, diversion fields and how the smaller aircraft are adapted. Also see the Just Planes Air Canada A319 video just released on a Toronto to London flight via St Johns.
Richard