Has taken me 3 months and every spare energy (thousands) I had to get her. Always had this "easy to get - stop crying" of some advice video in the back of my head while hunting for her. But I wanted this "starter team" everyone was supposed to have to get my account going. With only one legendary (Wukong) I wanted a decent team. Now I use her only for faction wars. Tundra and Tallia are a better help for my team. So - hunting for one specific champ? Only if this one is really missing. Compare her with what you already have and look if she can´t be replaced by some champ you have and can do the same or better.
oh hey it's the thread that never ends.
Warmaiden is pretty much only necessary if you don't have another 60% defense down champ on a 3 turn cooldown usually. Any of the epics like Dhukk, Deacon, etc. are markedly better. As well, Warmaiden can be left at 50.
Defense down is important though, so if you don't have it then she's worth getting/building to 50.