Multiple keyframes editing and falloff editing for Pose & Object mode.

Daniel, Matias, Antonio and Joshua developed this amazing thing for grease pencil cloud.blender.org/p/hero/5a2e96ee9379302dfb6ef1ce

Which in 3D animation would be a blessing!, it should work exactly the same as it works in grease pencil, select a bunch of keyframes edit the "reference keyframe" (the one where you're standing in the timeline) but it modifies the other ones smoothly from that point in time outwards.