Also, they did that because the 777 has a yoke, and the 787 was designed to require the absolute minimum cross training.
Excuses, is that what they are going to say in 2025, when they make the new plane, "well we made it so you could come over from the 787 to the 7XX more easily" like how the 777 before it, and the 767, 757, 747, 737, 727, B-52, B-17. They need to put in a joystick of some sort, after all it is going to be a new generation of pilots flying, not ex WWII pilots that can't adapt to modern technology.
I'm just saying that not having a yoke is both a weight saver, and is proven in fighter jets and the C-17, so they can be used easily on heavies. The pilots that fly both the C-17, and commercial jets say it does not take that long to get used too.
Also for safety it is easier to exit the flight deck during an emergency, less equipment in the way, and your knees can slide out with out hitting any thing.