Helen Noel had great chemistry with Captain Kirk. I'd have totally bought her being an unrequited love interest more than Kirk/Rand.
I'm not sure "Unrequited" is the right term. Rand might have had a school girl type crush on Kirk, which I think fits that term. I can't see anyway Kirk would take advantage of that (at least not while he is one person with good and evil in balance).
Noel is no schoolgirl and I can't see her putting herself and her career on hold waiting for him to decide he should get seriously involved with someone on his crew.
Ironically, the Rand/Kirk dynamic I think plays better and allows for easier writing. Noel/Kirk would be much more complex and very hard to work into episodic TV.