We finally have a new serial terminal. I have found "Gritty", a Java VT102 terminal emulator widget, which I have now integrated with the Serial Terminal (and adding it to other areas of the IDE as well) for much better operation. Proper ANSI control support, resizable, etc.
At the moment it is set to a predefined initial window size, but plans are afoot to make it remember the size like the IDE window does.
Post any problems or issues you have with it in this thread and I will get right on them.