I agree that 16 crazy, ruthless people might be more fun than just 2. And I love GoT, too. It was a tough choice between Cersei and Claire for avi. But what I love about the Underwoods is that they aren't crazy. They're completely sane. There's a certain amount of madness underlying most of the GoT characters (Cersei in particular, and I know he's boss, but Stannis is a little off his rocker with his R'hollr business), which makes their actions less predictable. It also makes them very much susceptible to death. Claire and Frank are playing the long game. Even if you don't know why they did something (aforementioned Meecham situation), you can bet they've got a good reason, which will eventually be made clear to you. Also, even though you know they're not really good people, you want the Underwoods to succeed. They make you want them to against your better judgment.
I think this season has a lot of promise because Frank has the office now. What will he do with the power he was working toward? Will his actions be constrained by his new role? I'm sure there will be a good numbers of challenges to his power this season. When these situations arise you see Frank and Claire at their best, and you get to see how their relationship works, which is one of my favorite aspects of the show. It's also going to give some other characters the opportunity to become stronger characters with their own agendas. I think Jackie is not content being a pawn. She's may end up being a thorn in Frank's side, which might be her undoing, or maybe she'll find a way to achieve her goals within the Underwood system. Anyway, I think it will allow for more of the complex overlapping objectives which you're looking for.
I guess I just liked Game of Thrones so much when this came along it felt like a little bit American copyism at work also. Oh? Ok, watch us do sex, power, mongering, and the brutality at work, we can do be edgy too. Having seen some I can say it is still viable to make it more interesting than most shows.
I just feel like Game of Thrones, is really about the game, and power, and chaos, but also relationships, forgiveness, respect, romance. Yes there is a lot of sex, perversion, silliness, violence, but it feels largely incidental to the collisions between characters and competing goals. Is it even really a violent series at it's heart? It almost just seems to be about momentary pleasures and concerns as much as anything, and oftentimes There are dozens of scenes of just people talking about their exceedingly simple trials and tribulations. It seems quintessentially American to take diverse subject matter and make it about the one almighty goal in order to drag everyone into their struggle.
That said though I see the validity of the show vis-a-vis all the other crap on TV that I never really watched at all anyway, so I can see the part where people get into it.