The Romulans dont ascertain reappearance until the Federation's first encounter with them visually in 2266. (TOS: Balance of Terror)
After the Earth Romulan War, the treaty and negotiations, neither side knew what the other looked like or ever faced them.
Presumably the writers Don't wish to incite canonical changes that dictate the original history.
Well technically considering the fifth to sixth doctor regeneration is very similar with swirling faces
And the second doctor had swirling in his regeneration
An article about this particular costume (link here) includes an interview with one of the costumes designers Aggie Rodgers.
... she remembered that Lucas pointed her in the direction of a
specific artist for inspiration, Frank Frazetta, whose illustrations
of fantasy and sci-fi characters like Conan the Barbarian and John
Carter of Mars have made ...