I tend to agree that a family relationship season would be the most interesting. I'm also not a fan of a dating couple edition. Although I liked Season 6, there was WAY too much drama for the average viewer to have to absorb.
One thing I don't like (that TAR has been doing with increasing frequency lately) is casting too many nebulous teams of "friends", whose relationships are officially listed as their occupation instead of their actual relationship. We've had way too many teams in this category in recent seasons, and I've gotten really tired of hearing the same old spiel: "As [insert occupation here (firefighters, globetrotters, cowboys, country singers, etc. {they're all the same thing anyway})], we are used to [insert a skill or ability here (thinking on our feet, interacting with people, navigating, etc.)]. Such casting tends to ruin the relationship element of the show that Peach referenced. Therefore, I think there should be at most 3 teams of friends in any one season. Any more than that, and it starts to feel like each team is just there to hog the airtime and distract from the other teams (and irritate me beyond all measure).