Most of the time keyframes are set relative to a clip's in/out/middle point(s) and/or other edit points in the Timeline. Keyframes are seldom set relative to the content of a clip alone.
For this reason, users need a simple way to decide if keyframes should slip along with a clip or not.
The solution is SIMPLE!
Slip = keyframes DO NOT move when slipping a clip (new default behavior since this is what most users want most of the time)
Ctrl(Cmd)+Slip = keyframes move as they currently do when slipping a clip (when using this keyboard modifier, the slipping icon could show a keyframe icon to visually inform users that keyframes are being slipped as well. See illustration).
Note: for users that prefer the current behavior, a new option in the Preferences window could allow users to reverse this functionality, i.e.: Slip = keyframes move together with clip, Ctrl(Cmd)+Slip = keyframes don't more.
This solution would work for ALL editors, since it would give everyone the option to easily choose on the fly if they want their keyframes to slip in tandem with their clip or not.
This is one of those quality of life improvements that would make a huge improvement in Pr's editing workflow! Please add this much needed functionality!