The key behind these improvements was thinking about motions differently, by treating an emulated Wii Remote as a virtual object acting out these motions, Dolphin now handles a lot of the extraneous motions that swinging, tilting, and pointing a Wii Remote does that aren't immediately obvious. These efforts have greatly improved Dolphin's ability to create motions that games can recognize without the need for real Wii Remotes.
In a dramatic return to the project after a long hiatus, Billiard returned to the project with the goal of cleaning up emulated Wii Remotes and implementing emulated MotionPlus correctly once and for all.
Your eyes are not deceiving you, MotionPlus emulation is finally here.