People are forgetting her mace is an AoE attack not a Single Target attack. Which means she might be poor at 1 v 1 but she works great in doing group damage.
Her burst damage is only around 155 - just enough to kill a tracer.
Her passive heal is only meant to heal poke damage. Where she is going to suffer most is, unfortunately, is long to be point B on most CP maps while playing defense.
The reason being her low shield health and low mobility is pretty bad for long range engagements.