In what sense? An attacker can already see the endpoints of a TLS conversation, and worrying about hostname disclosure is security through obscurity; the client already divulged the destination hostname with a probably-cleartext DNS query, too. Not worth worrying about. SNI is fine. If hostname disclosure is a security threat, the system needs rearchitecture.

Systems that hostname their customers (mycompany.example.com) should use wildcards for that scenario instead of SNI, among other reasons. That’s the only possible concern I can imagine.