Drag to change video speed

This is a duplicate suggestion. See here:

This is a good idea and we will probably implement it some day.

Keyframing the time remap filter might be easier than the “guess and check” method. But still not as good as the click and drag suggestion.

Also, since you mentioned waveform matching, have you seen the Align to Reference Track tool? It can automatically adjust the speed of a clip to match another clip with similar audio.