Those features you listed would be nice to have, but I don't think they're 100% essential. I have a suggestion that I think is even more important:
* Tunnel needs to follow the text cursor
Without that I have to type and move the mouse simultaneously, and I can't read through text files with just my arrow keys.
This software is emminently useful as it is though, but if it can follow a cursor, it'll be ready to add features.