Right now we have global and local variables and it works really well. I might suggest adding layout variables. The reason for this is that a lot of time I use triggers and other level specific game objects.
Having a layout variable would make things look and feel a lot better. I could see what variables are in that layout. If I use the trigger example I currently have to label them like this
TriggerL1T1
TriggerL2T2
ect.
But with the local variable I could just say
TriggerT1
ect
On top of that, if they were a different color at the top it would make things visually easier.
Just a thought. Keep being awesome Scirra.