well, it's the federation design and they need deflectors. if they don't need visible ones, then how come all of them have one? it's part of the design. sure they can have like a small one somewhere on the saucer section but it needs to have a forward allignment. perhaps they are more hidden. however the saucer does not have any warp engines. it has impulse engines but not warp. if you find warp engines on it, let me know cause for the life of me i can't find them. i'm not saying that the ship is not capable of warp if modified, but it didn't have them. i think what you were pointing out in farpoint where they separated and saucer seemed to still be in warp maybe is just because of inertia. i think that was just a mistake though cause as soon as the saucer left the warp field generated by the drive section, it would have dropped out of warp.