Boodendorf
Bird woman!
Same thing usually happens for me, just wait for the DLC chars and in the meantime I'd just recommend learning the character that you like the most non gameplay wise.So far in Injustice I've been through most of the cast and just can't seem to settle on any one character.
To be honest the only game I've ever gone "this is the character for me" and stuck with them is Venessa in Virtua Fighter, and I'm really not sure what it is about her and her playstyle that grabbed me.
Does anyone else have this issue in settling on a character or am I just a finicky blighter?