Volcarona is to Blissey as Zamazenta is to Dondozo. It keeps many of the key special sweepers like Ghold, Darkrai, Raging Bolt, Kyurem, and Iron Valiant in check, while also losing quite easily to many of the special walls like Dirge, Clodsire, Blissey, Toxapex, etc. Its much better at avoiding momentum loss vs offensive teams than blissey the same way zama is better at avoiding momentum loss when compared to Dondozo. In that sense, I am confident its reintroduction would be a good addition to more balanced teams to give them an easier time combatting offensive teams. From what I remember when it was legal, it also completely annihilated Darkspam teams, which may be a good or bad thing depending on who you ask.