http://www.valvesoftware.com/email.php?recipient=TF+Team
I just sent the tf2 dev team an email. If everybody who sees this post does the same, the bug will be fixed in the next major update, if not sooner. Remember, in the (not so recent anymore...) blog post about balance changes, players were encouraged to send the team an email with any feedback they might have. They definitely read these emails.
If you're reading this, send a quick email. It can just be the link to this thread and "sticky detonation delay" in the subject if you want. Don't leave it up to everybody else to send emails.