I think having couples could be counter productive as they are likely to be inhibited as to how they behave with other housemates of the opposite sex in front of each other.
Being established couples they may well get frustrared during the 9 or 10 weeks run of the show and perform so to speak for the producers.
But what is the point. They would not dare show anything that's not suitable for the "blue peter" type audience they target.
Jades little shuffle under the blankets was about as interesting as a cold cup of water. Why should a "Couples" shuffle under the blankets be any the more interesting.
I do hope they have 12 "Hot blooded" strangers and let brand new interactions begin and who knows perhaps there won't be any blankets to cover them.
Ofcom will be watching. You bet.