Boeing investigated mechanically coupled side sticks in the 757 development simulator several years ago. The 777 went with a conventional stick, in part so as not to follow Airbus, to keep all Boeing flights deck standard, and that improved technology was not then available. However, modern side sticks can be cross coupled and dynamically back-driven giving the crew all of the characteristics of force feel and control feedback. There are many arguments as to which type of control input to use, probably the new side sticks being just ahead, but my money would be on the 7e7 having a centre stick and a 777 look-alike flight deck.
Pilots and designers rarely have as much sway in these decisions as do the marketing teams i.e. keep the same flight deck, fleet commonality, and reduced training costs. It is unfortunate that these types of decision may hold back the industry, some preventing safety improvements … why doesn’t the industry update the FMS keyboard etc, it may be a poor design but it’s the standard.