What I think Titan means is that on the Geoscape, you can visably tell the difference between the UFOs, despite not having researched them. I agree. This makes it too easy to say "Hm. Thats a Fighter. I wont send my interceptor to attack because I know, at this point, the Fighter is superior."
X:COM had it right to only say its size (Small, medium, large, XLarge, XSmall), and I think this would be good until the ship has been researched or adv. radar is in place.