She needs a rework. Her current state is boring to play as and frustrating to play with or against, and it completely fails to capture the fantasy of a Siege Tank.
She needs less durability and self-peel.
She needs more range.
She needs to rely on her allies to grant extra vision.
She needs higher DPS in Tank Mode than in Siege Mode.
She needs more splash damage and area in Siege Mode.
She needs OBFG replaced with something more interactive.
Those are the major things I think she needs changed.