I rather think that devs' time would be best spent ensuring that our
tools against Tor users and open proxies are effective and reliable.
Huge amounts of volunteers' time are spent combating abuse of them, with
inadequate tools.
See for instance:
https://bugzilla.wikimedia.org/show_bug.cgi?id=30716
https://bugzilla.wikimedia.org/show_bug.cgi?id=42438
https://bugzilla.wikimedia.org/show_bug.cgi?id=8475
As for legitimate users, probably the most useful thing to do would be
ensuring that the TorBlock extension shows an understandable error
message and sends people to a translatable page with instructions valid
for all language editions of our projects with current poliecies (most
projects will have none).
Nemo