Something I think would be very handy are some extra keyboard commands for the event editor. As it is, you can already type your way through the event wizard - with these, I think it would satisfy the people who like to type code, and assist those who like to do the one hand on keyboard, other on mouse method.
E: New event below
Shift-E: New event above
S: New subevent
C: New condition
A: New action
D: Toggle disabled
G: New group
F: New comment (not sure which key would be best for it - W?)
Space - collapse/uncollapse groups
left arrow - if an action is selected, it selects the nearest condition to the left. If a condition is selected, it selects the event. Right arrow goes in the opposite direction.
Up/down arrows - goes up and down in the currently selected column.
Holding shift with up/down selects multiple ACES in that column.
Holding ctrl up/down moves the ACE in the column.
Also handy would be the ability to set the keys used in the properties - I for invert is far away from the other keys, for example.