Our new Romulans are covered in tattoos
Our new Klingons have piercings and helmets.
The Romulans had the Tattoos for a mourning ritual, that's not necessarily the look of all Romulans.
TNG is the one who really, really changed Romulans by giving them those huge Forehead ridges. In TOS, Romulans looked just like Vulcans
Yup, never really understood that one. Especially since the only real difference between Romulans and Vulcans is their location.
I always rationalized it (not that you need to, but just for fun) as the Romulans genetically engineering a lot of their people to resist the effects of mind melding and psionic weapons like the Stone of Gol (TNG - Gambit
) during or after their schism with the Vulcans. It had the side effect of rendering the Romulans with the ridges incapable of telepathy, while the now minority non-ridged Romulans can still do it with the proper training (and the closely related Remans can as well).
Up until their relationship with Vulcans was exposed in TOS
, the non-ridged variety had a far greater presence in the Romulan fleet, and perhaps were even considered a more elite caste in their society due to their unaltered genetic makeup. The ridged variety could have been the soldiers under the helmets.
But any Romulans who interacted or could interact with Vulcans (like those in ENT
) and later after their reveal almost the entire Romulan fleet was switched to the ridged variety because they couldn't be manipulated or read by their Vulcan enemies. The non-ridged Romulans fell out of favor with the new government due to their decadence and later took on more menial jobs, like the miners on Nero's ship (they had ridges, but more subtle ones).