My feeling is that release dates only should likely be kept, as they're more concrete and better known.  My only reason for bringing in N64's controller unveiling at Shoshinkai 95 was to illustrate it's influence on the direction Sega and Sony then took with their controllers in response (which may not be apparent from the actual release dates).  But maybe a neutral statement to such should be mading reference instead, the sourced 1up article in the N64 paragraph already makes specific mention of that. "And by showing off the new controller with a polished (but not complete) version of Mario 64, Nintendo showed the killer app that made the thumbstick more than a gimmick. Sony and Sega saw the writing on the wall: next generation meant 3D, and 3D meant analog. They immediately set out to create analog joysticks for their consoles. Sega actually moved so quickly on their design that they beat Nintendo to market in the US (though not worldwide)."