My understanding is that airbus will lighten the ZFW, up the MTOW, and get the 14% improved burn from the Trent engines. Thus gaining an additional 400nm range, but significantly improve on its full payload range (as the 332 has the range but without any payload, TLS-HNL). John Leahy said in the press release for the neo that it would be capable of HNL-LHR. We shall see..
What's the obsession with HNL-LHR? Surely if this was some gold mine of a route BA or Delta would already be flying it.