In a two engine aircraft with one engine failed, there is only one reason not to come back and land asap (with appropriate checklists and approach preparation complete) and that is performance (landing performance or go around performance). Even then you can decide to waive those requirements if for instance you have a hugely long runway, cavok, and no obstacles.
I look at it this way. When you are responsible for passengers lives, be it one or 400, then you must always have a contingency plan. If you have already had one engine fail, then what is your contingency plan if you are away from the airfield dumping fuel and the other engine fails?
You are in a fair bit of trouble I would say.
It is not logical to apply the ETOPS theory. The only reason we fly for 3 hrs on one engine in the ETOPS case is because we have to. We would never overfly a suitable airfield on one engine just to get to the designated ETOPS alternate.
That's my two bobs worth anyway