The B787 was designed for a 2-4-2 seating configuration but IIRC there are only two airlines, All Nippon and Air Canada which ordered it like this, everyone else went 3-3-3. I flew one eight hour flight in 9 across economy, luckily the aircraft was half empty and I got a full row of seats but it still felt cramped.
The return flight was on an A350 which was a pleasure even though the cabin was almost full. This is now my aircraft of choice, ahead of the A380.