Something that I'd like to see (it isn't particularly flashy but would be very useful) is a GUI to keep track of global variables. You would use to the GUI to add variables and their initial values, then use the entity properties dialogue to change the values. You could, for example, have "If killed/destroyed" and "If activated" fields in the entity properties, which you would then use to change the values of the variables. For example, you add an 'experience=0' variable to the global variable list, then add 500 to the experience variable in the 'if killed/destroyed' field of a particular entity, or add 500 to the 'cash' variable of an entity representing money. You could also create a disposition/morality system this way. Killing or collecting an entity could cause johndisposition to increase by 100, and jimmydisposition to decrease by 100.
I understand that this is already doable using scripting, but since FPSCR is aimed at lone users or small groups, anything that saves time would be a big help, and I think that this would save a huge amount of time.

An interesting idea.

SC

Something to go along with this could be the ability to have fpe files honor custom variables and display those in the object's property pane. And not only should you be able to add them to the fpe and edit them in the editor, but you should be able to get/set their value in script such as g_Entity[e]['mycustomvariable'] = "something"