Some things I have noticed in script editor:
when autocomplete offers completion string and I accidentally type a lowercase character (that is the same as in string with different case), autocomplete will concatenate whole string, not just the part needed. For example, typing PythonQtd will offer PythonQtDebugAPI, but pressing enter results in concatenated wrong string: PythonQtdPythonQtDebugAPI
for convenience: commands like print etc could use different, lighter color schema for syntax highlight, they are very hard to read on dark gray background;
for convenience: when typing a command and autocomplete offers something, pressing tab could also apply the completion, currently only enter works.
Regarding Qt access, it seems to me that not everything in QtCore and QtGui libraries are accessible from script editor, only a small subseet is presented. I have looked for PythonQt (which I believe is used for adding python support here), it is not accessible at all. Qt, QtCore, QtGui modules seem to only present a few select classes. Is there a reason for this?