The capability of running headless, ie. without GUI, is a very welcome addition to QCAD. I suggest one more improvement:

When an exception occurs in a script (running from autostart) and no-gui was opted for on the command line, QCAD should not try to bring up the debugger ever (regardless of any preferences), but print the message of the exception and possibly a backtrace instead.

Otherwise all errors will produce the same message…