Marc,
I agree it's nice that all readable european, asian, etc. characters come out unescaped, but it's weird to know that Gambit would come not-copy-paste-proof out of the box, and that you need a specialized script at startup to fix that.
I use the best terminal software and it does not show all unicode characters;
for reference, attached a screenshot of how messed up unicode shows in Chrome and its DOM inspector, so this is how a Gambit console window could look. In itself not too bad.
I would primarily suggest that a command line option would be added that configures the escaping e.g. -:E , -:E127 (or maybe -:T127 for terminal and -:F127 for files).
Secondarily I would suggest reverting lib/_io.scm:13119 back to (##integer->char 127) i.e. escape all >127 again, as at least I find this to be really more a "safe by default" behavior.
Anyone else has any thoughts on this topic?