They shouldn't start over at all. Just do it better.
Of course they need. If there's a chance to undo everything post CV then I'll be happy if they take it. And you should be too, especially after knowing how much do you hate the fact that capcom killed umbrella in a one-paragraph intro.
Though Umbrella hasn't ever really been 100% gone.
Its gone, all that was left were posers as Tricell and that awful neo umbrella.