Say'ri wasn't all that bad for me when I used her (and I don't really grind in awakening all that much) A better candidate for 13 would be yarne because he comes in at a time where you can't really use him without grinding.
And Orochi is nowhere near bad. Her Magic stat goes way high up to make her much better than hayoto. Plus that capture skill that let's her get other good units like danialla with a savage blow already on her.