It is the dumbest shit ever. All you should have to do is mark the camera path with position keyframes. You set the key frames, then tell it how fast to move between the points. forgot the time keyframe crap when all you need is a little input box. Not to even mention the fact that the 2 timelines are not auto synced, when, one is playing the other should be synced so i you don't have to go and find the spot on the other. Even a 5 year old knows it makes more sense to work that way.
v is the default hotkey to sync the cursor in the keyframe timeline to the current time in the replay. Hold it to keep it synced.
But time keyframes are neccessary for the Replay to know when in the Replay to start and stop recording. I mean yes you could fill that into a box but then you'd have to go back and find out when exactly you want the recording to start & stop. Plus, time keyframes are very useful if you want to make the video slow down or speed up at certain points and make some really cool timelapses. And they aren't that difficult to add, right?