I think there should be a (opt-in using the settings button) feature in Snap! where, using serveral blocks, you can output to a debug console of sorts. This would be pretty useful for complicated projects. Here is my mockup:

log would log a normal info message to the console, warn will be a warning (orange), etc.
And clear would clear the console (should also be possible from thje console itself)
The console should be opened by a button (possibly near the stage buttons, or the Snap! topbar), and, again should be opt in.
One issue is that really theres nowhere to put these blocks. Maybe in Control or another category or just make a category only visible when this option is enabled.
Of course I'm not expecting this to actually get in Snap!.