Ok. Then my approach would be to keep things as they are until someone comes up with a specific complaint. :-) As I said, the box drawing stuff is fixed, so feel free to raise a new issue if you find something else which is a concrete problem.
(As a side note, I think you were justified in assuming thick/double lines was a font issue. There is no semantical difference, so I imagine the only reason why Unicode assigns separate codepoints to them instead of treating them as font variants is for compatibility with some other encoding that has both...)