Just caught up with this, I thought Caroline and Adam had the best rapport out of all the couples, yes she's bossy, but he keeps cracking his jokes regardless, they found fun in the situation whereas all the others looked tense. I bet he keeps half his figurines! I can also see them parenting together which I couldn't see any of the rest doing.
I don't know why everyone thought Clarke and Melissa were the perfect couple, they clearly had sexual chemistry from the second they met, but that interview on day 10 was reserved and he in particular didn't seem to be very enthusiastic. I think their decision to part and see if they wanted to date was the right one.
The other couples wouldn't have even gone on a second date if this had been a normal way of dating.
The scientific method is utter pants. It's well-known that if you pair off people in their late twenties and thirties, who want to be in a relationship, some of those will stick. It's what dating agencies do, except they don't bother with all the 'science' and 'mumbo-jumbo' they just spend about 5 seconds matching basic descriptions (dark-haired, works in finance) and they probably have a similar hit rate.