Wikimedia Bugzilla is closed!

It would be helpful if we can see in the history of an article when the artucle
was blocked and when it was unblocked.

IMHO this can easy be done: If an administrator blocks an article you could
create a new version and add the comment

        "Blocked by <usernam>: <reason the administrator entered>"

For example if administrator tsor blocks article [[abc]] and enters as comment
"serious edit war" the history show a new version with the comment

        "Blocked by tsor: serious edit war"

Same procedure for unblocking an article.

tsor - administrator of german WP