hateHate to despoil the trek mythos, but in the tngThe Next Generation sequel series before discoveryDiscovery and picardPicard, the main visual difference was that the romulanRomulan brow was more prominent. Watch the visual differences between enterprises tpolT'pol and tng'sTNG's Romulan captain Picard plays chess witwith so often , Tomulok. vulcansVulcans only look different to humans by the ears whilst the romulanRomulan brow ridge would give them away in a flat second. And no iI am by no means confusing them with klingons,Klingons; watch the videos where they talk about the makeup actors have had to have placed on them to play romulonsRomulans.