always unwrap wrapped text when newline occurs at the edge
This is my biggest issue with iterm2 at the moment: when software such as tmux looses distinction bw soft and hard line breaks, it's a pain to copy text in iterm2.
The workaround discussed here https://gitlab.com/gnachman/iterm2/issues/3590# is not good enough to resolve this issue [we can discuss more on this if needed].
So I have a very simple suggestion: use heuristic (either as default or option) which will unwrap [join] lines when the end of line occurs right at the edge. The edge being determined by current heuristics for horizontal pipes '|'. The unwrapping would occur during copy.
PS: I've asked on tmux https://github.com/tmux/tmux/issues/65#issuecomment-124951611 [tmux is not preserving the distinction between soft and hard newlines] and their answer is that tmux doesn't seem to care about distinguishing hard vs soft line wrap (probably for efficiency purposes during scrolling although I wish this could be controlled by a flag).
PS2: one issue with proposed solution in 3590 is that the unwrapping logic occurs upon pasting, not upon copying; so if you copy in iterm2 and paste in another program you still have the bug. There are other issues.