Better Accurate Trimming support
Currently the user has to choose between fast trimming and accurate trimming. Ideally there should be a mode which is fast and accurate (#14 (comment 978153)).
Further more there is no indication that the selected range and the resulting video will be different which makes the default behavior unexpected. I have anecdotal evidence that some users just assume this to be a bug in the software. The checkbox in the save dialog is not a common pattern and thus not discoverable even if you are searching for such a feature.
Visualizing the keyframes (#9) would resolve some of the issues but again ideally the trimming should just always be fast and accurate.