Actually, in PHB, the ranger gives up an action, or one attack if extra attack, to use the beast.
In new version, ranger only gets one attack while beast gets other attack. So if beast dies, you still have only one attack. Its actually worse.
You could also argue that it's better in the sense that it doubles your hitpoints. All the damage your pet just took could have been damage that you would have taken and been killed. Instead, the pet took all the damage and while you lost that attack, you do still have one attack, plus your other abilities, and your hitpoints. Still alive with one attack is better then dead with no attacks.