Good article on genesis of Ariane 6 configuration and its challenges. In the beginning, Ariane 6 was supposed to be modular. At this stage, it seems to have only one configuration at 6.5T GTO. That’s a pitty…Specially now that developments in electric propulsion could change satellite masses dramatically (up to – 50% – of course with increase in time to orbit…)
Additional details on A330NEO development….Very attractive concept: performance, no introduction costs, price (in principle). If developments costs mostly on Engine side can be contained, I would tend to say it’s going to happen!
Aviation Week article: