Are superluminal sensors dumb or would it be dumb if they didn't exist?  I'd say it depends on your in-franchise physics.  If ships in the franchise use hyperspace, slip space, or some other equivalent then maybe it makes sense not to have it.  Very few franchises actually have superluminal sensors.  Stargate doesn't.  Babylon 5 doesn't.  Battlestar Galactica doesn't.  Andromeda doesn't.  In most of these cases, they don't even have the ability to communicate long distances except by courier.  (Star Wars has the holonet which works through the hyperspace beacon network.  While B5 uses the Jump Gate network for the same effect.)

Star Trek has superluminal sensors but then, they don't use hyperspace.  They fly in real space by bending space in front of them, thus shortening the distance between two points.  Having such sensors makes more sense for them.  They're also one of the few franchises that can have battles while moving faster than light.

[@Sophrus]
Superluminal sensors *could* work if there were some sort of particle that moved faster than the speed of light like the mythical Tachyon but yes, you're right, with today's physics it makes no sense.  Maybe if someone could bend space... but then, if you could do that you wouldn't need to direct your sensors there, you could just be there and use your own eyes!