War is not an option. The quarian people couldn't beat the geth at the height of their glory, and now that the geth have been expanding, making more of themselves, and adapting in new ways and the quarians... have not... there's no way that the war would be anywhere near successful. If Shepard did Legion's loyalty mission, the only remaining Geth are those who bear no true ill will toward the quarians, but are nonetheless very wary about them, considering, y'know, the quarians shot first. At this point, the only options for the quarian race is peace with the geth or extinction, one way or another.