Yes, but that merely limits the damage to a small degree. Fighters need vertical stabilizers because they require higher maneuverability than flying wings. And current aerospace design capabilities can't overcome it, though bendable (wing warping technology) wings might eventually.
Yup, thrust vectoring will help add control authority. But vertical stabilizers don't necessarily contribute to the amount of G's an aircraft can pull. It depends on how they're measuring it. With an aircraft lacking VS, you could simply pull/push up down to get high G, or roll and do the same.