Since the clearnet domain is facing a lot of attacks, shouldn't the better solution be that the clearnet be just used for informational purposes about Chipmixer and also a link to the tor version that the users can use to mixer coins. More like a move pushing users to mix through the tor version.
I would like to tweak that suggestion of yours a little bit. They should definitely create a new clearnet website since the old one no longer works, but there shouldn't be a link to the onion website. Instead they should link to this ANN thread and instruct users to check the OP where the correct onion link is posted. Or at least ask customers to verify that the posted onion link on the clearnet site is the same as the one that appears in the Bitcoin ANN. Just in case the clearnet version gets hacked and someone posts a link to a fake mixer. Someone could of course post a link to the wrong Bitcointalk thread or a completely different source, but I think the potential damages are smaller by linking to the ANN thread as well.