The telum looks like the last visages of whatever Vulcan design hierarchy was left in the Romulans as they began their own shipbuilding program.
...or am I reading too much into a color experiment with red
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?
I like the crest on the bow of the Sagum. Taking it further you could call it a hallmark of Reman ships in the TOS/Early TMP era. Maybe it eventually evolves into the decorations on the bow of the D'Derix.