So since my computer is too modern for this file, I will have to base feedback on the video.
Thing that need to be fixed include the events and teams as you said, as it appears plotting the coordinates of worms is a bit sketchy.
Correct me if I'm wrong but at present this thing can only edit missions, not create them? Would be nice if you could create your own missions with their own unique briefing, etc.
Support for Windows 8/8.1 would be the icing on the cake, but I'm not sure you know how to do that.
At the moment, I'd rate this as 2. Lack of support for 8 is the main factor for this, but if this can't be fixed, then so be it.