Why doesn't Rip just deal with his wife and son's death? I mean it's extremely stupid to just go back in time with a bunch of people you don't know about and have them screw up the past with you. And if they did manage to kill Savage he's just gonna comeback and piss in everyone cheerios.
Why doesn't Rip just deal with his Wife and Son's death?
No, its not about just the loss of his family but about humanity too. Vandal Savage is ruling the whole world, so just dealing with his family will be too selfish for a person like him.
Why did he go back in time with a bunch of people he didn't know?
Rip goes back in time to save the world from Vandal Savage's rule. It was not his first attempt:
Rip had tried to kill Vandal in ancient Egypt when Vandal was not immortal but he failed to do so. So Rip changed his approach.
Rip chose these people, which might look foolish to you, because
Their disappearance will only have a tiny impact on the timeline. This is the same reason that Rip doesn't select Arrow or Flash.
They lack in experience for sure. Sara was assassin not a hero as do others, so they all need time to learn "how to save the world'. That's the show is about, a time traveler trying to save the world with misfits.