I don't know what DigiCert's motivation was for suspending issuance of .onion certificates, but the CA/Browser Forum had given a special dispensation (by ballot) for issuance of EV certs despite the criticism about cryptographic strength mismatch. This dispensation didn't extend to DV, but it's never been revoked, so DigiCert would still apparently be able to continue its EV issuance if it wanted to! (But it looks like they've even let the facebookcorewwwi.onion certificate expire.)

I've recently become an observer at the CA/Browser Forum and plan to bring up the subject of DV certificates for next-generation onion services imminently, just as soon as I'm done with my relaxing vacation!