On the topic of Spock/nu Vulcan having arranged marriages/breedings - that seems short-sighted. If anything, Vulcans should be encouraged to breed with humans. We've seen that Spock, a vulcan/human hybrid, seems to be, from a physiological standpoint, almost completely Vulcan. Given that he was able to succeed in Vulcan society, to the point where he was offered a slot at the Vulcan Science Academy, there seems to be no intellectual downside either. If Vulcans can get over their superiority complex, they'd see that the logical choice is to have more relationships with humans, not fewer.
IMO it's unlikely the Vulcans would drop their superiority notions - logic doesn't seem to take them that far. Even if it did human - Vulcan interbreeding would only work if such unions were naturally fertile and produced fertile offspring. Until and unless canon states otherwise to me Spock was the result of painstaking genetic engineering and is infertile.
To answer the original question, I would like to see an ummarried couple, or triad or Denobulan type family etc with children as much as I would like to see the same family with married parents. Not at all unless it has something important to do with the plot. Were the little girl's parents in STID married? I don't know and I don't care.
I'd rather them spend time showing a woman captain/commander who wasn't someone's girlfriend or Admiral's daughter. And only that too if it adds to the plot of the movie.
Absolutely! If I wanted soap opera I wouldn't be watching Star Trek.