Many basic facilities are needed, see further discussion:

1) Add real editing controls, so that one may move by small increments in _both_ directions to find the proper place to drop splits.
2) Allow assigning DVD index meanings (chapters, etc) to split points.
3) Allow resizing the playback display _and_ the storyboard editing window, to give a better view of what you're doing.
4) add 'crop' (name it what you must) that allows marking two endpoints, and throwing away everything but what is between them.
5) Allow playing in reverse, for quicker location of proper split points.
6) Give us controls to enlarge and reduce the horizontal scale in the storyboard window. While editing a 1.5-hour video file, I needed to cut off the first five seconds, then brake up the remainder into 8mm-reel-length segments. Once I made the first split, I couldn't make any more, because the first 5 second part was still hilited, and I couldn't tell because it was so small.
7) Moving the split point to a location outside of the segment that does not have focus should change the focus to that segment, so you don't have to move focus before the split button does anything.
8) Make better use of menus to make features available (even if they are not available in the current mode, have them listed and greyed) so that the user can see what you give them for tools.
9) Make help local. Not everyone has internet connectivity all the time!
10) Make a portable version, even if you lock it to the portable device it is installed on (for GOATD or normal installations) because no everyone who needs to edit videos can have install permission on the computer they need to do the edit on. (This may seem silly or impossible, but I just spent 6 years working there.)