Any place I can write a script should be able to check that the script will compile. I don't like finding out I made a typo only at run time, from a popup that says "Script could not be compiled." There is already a little red highlight next to the scroll bar, so the editor already knows there is a problem.

In any list of scripts, like when you Configure Events on a component, any invalid script should have something like the triangular warning icon next to it.