It appears BA has recognised the issue with the IFE boxes under the seats and at least from pictures I have seen the IFE box is thinner and less intrusive in WT+, there does appear to be more space in the A and K seats than the B or J seats for leg room, however, the box is far thinner than in the past (from very few pictures so this comes with a big caveat until people fly it!)
Is the entertainment box also less intrusive in WT? That's where it is the real problem on the 787, essentially occupying the entire space where you would want to put your foot (without having to angle your pelvic or knee joint). Has the A350 got a smaller entertainment box, alleviating this problem?