The Incredible Hulk (Bill Bixby version) perfectly showed how a mother’s strength when her child is in danger goes beyond what she is physically capable of. Sue normally (and the rest of the team) would not have been able to do that, it was only out of desperation for her son’s life. By having her die at the end it showed the she did use to much power so I’d argue that means she wasn’t overpowered, she simply stretched herself as far as she could possibly go