Have to agree with potnoodle 3-3-3 in Y is ghastly- SHOCKING when you consider that this is the boeing suggested charter configuration and will be fitted to the Thomson / Tui 787... and interesting to note that all the other posters have only commented on the CW cabin so far!!!
(Lets not forget that the 777 has this config. and has a much wider fuselage (or will BA revert to 3-4-3 in Y on the 777 like AA??))

Commercial reality... or not?
I would have thought 2-2-2 in CW, 2-2-2 in wt+ (similar to 767) and 2-4-2 in Y would have been a sensible layout.....

I WAS saving my Avios for a ride on the 787.... time will tell.