The "structural" similarity you call out seems way too vague to justify calling the one a variation of or reference to the other. Melodies ascend and descend; without a hard reference point like melody or rhythm or key or interval to identify between two, there's just not much to go on.
(Don't the pairs sometimes descend and sometimes ascend in the Courage?)
I'll change my tune (heh) if we learn that the intervals are the same between the two pieces. Then I would agree that the Courage is a nod to the Steiner.
The intervals are not
the same. That's obvious to me just by listening, and I never claimed they were the same. You're being too literal, too narrow. I'm just saying the one is reminiscent
of the other, and since they're both themes for Romulans, and since they're by composers who'd been working on the same show for two years and were presumably familiar with each other's work, it is not implausible that Courage may have been influenced to some extent by Steiner's theme -- enough to do a theme that was distinctly his own, but still evocative
of the Steiner theme.
And I'm not claiming it "is" a nod. I'm not stupid enough to confuse a hypothesis for a fact. The only way we'd actually know is if there was some surviving interview with Courage or document by him where he said it was so. Absent that, the most we can say is that it's possible. And that's all I'm saying -- that it seems plausible to me that it could
be, that I wouldn't be surprised if it was.