No, it is not equivalent, but it is also not sufficiently stronger to make it impossible to play the old version at the same table. The difference between the two characters is unlikely to be more than the difference between a weak 5e character and a strong one, for example.Is that rank feature equivalent to rolling twice once per round and taking the higher damage number? Not even close. It's got highly narrow usage and what you get during that narrow usage isn't going to be anywhere close to as useful as Savage Attacker.
Do I expect people to want to play with the new backgrounds, rebuilding their characters to do so if necessary? Absolutely. Do I think it will absolutely be required to have fun playing the game with other players who did rebuild? No, not really. In the end it’ll depend on what the new classes look like though, since that’s so much more of the power budget for a character.