While i do not think shaman is necessarily OPn ( as in uncounterable), i do think her kit may be a bit overtuned.
I would propose fixing/changing:
wildcats rage indicators (which have been reported and unadressed for over a month).
Her dodge recovery (it simply makes her too difficult to punish).
Her damage and/or the ability to get predators mercy/hunger on GB (although this will be less relevant on the release of parry changes).
I have played shaman to rep 3 and she is incredibly easy to perform well with - especially in team modes. My KDA in team modes is double that of my main (which is PK - another very good character).