Therin lies the problem, every other strategy I have tried(lair, kinship, fellella, forge, rajan's fury, etc...) ends up being better as the straywood beastmaster. I have only found attack spells to have the synergy with her strengths to augment her more than the straywood. Being able to double dip on the hawkeye bonus is just an extra bonus, but not the main reason. The reason is simple, she cannot field as many creatures as effectively as the straywood. If she does not have creature superiority, she must either eliminate creatures or perform some kind of completely bizarre positional sleight of hand to go for the throat (good luck with that against most mages).
The strategy works well, but it's just a few too many points in the book. Not many though, that is why I feel she needs cheaper access to one and only one attack spell.
As for the mana issue, mana is not an issue when you are spending a full action to fire the bow often enough. (again, if you aren't using a bow, there is little reason to use the johktari). All told, a beastmaster only attack spell would affect her far more than the straywood and bring the two on even footing without affecting any other mage.