I don't believe that strength should directly correlate with the importance of the character. Tyrion's strength being lower than Jaime makes plenty of sense to me. He was obviously much stronger in battle than Tyrion and as for his intrigue, I'm not sure. On the one hand, Jaime basically hates the courts, explicitly saying he has no interest in them or in politics. And he's not particularly good at it, as a lot of people call him Kingslayer. On the other hand, Jaime was also incredibly well respected by the people who mattered. Not only was he a renowned knight growing up and the youngest member of the Kingsguard ever, but he was in the ear of the Queen as his sister, the king as his guard and the eventual hand as his son.
And Tyrion, although he is skilled in intrigue, is often mocked or derided by those in power, even his own father, because of things outside his control. He is hated by his father for not only being a dwarf, but also for killing his mother in child birth. He is hated by Cersei for sending her daughter to Dorne, even though it was a very sound way of guaranteeing the Martells don't join the war, and immediately accused (and convicted) of murdering Joffrey, despite there being no evidence against him.
So I guess the question is, what should strength signify? The perception of a person's ability, or the person's actual ability? For the former, Tyrion's and Jaime's ratings make sense. For the latter, Tyrion should be a 10.
I think the only reason they gave him an intrigue icon is because such an iconic character shouldn't be a monocon (*cough* Jon Snow *cough*). Otherwise, you could make an easy case for him as a military monocon.
In the same vein, Margaery as a 3 strength support character makes perfect sense to me. For the first 4 books or so, she is mainly a piece of someone else's scheme. She is married to Renly as Olenna's plan to get a Tyrell into royalty. She is then married to Joffrey as part of Littlefinger's plan to win Tyrell's loyalty in the war instead of Stannis. She is then married to Tommen, because Olenna killed Joffrey to protect her. There are implications that Margaery knew of the poison, but no implication that she had anything to do with the scheme.
Even in Feast for Crows, it is primarily Cersei that is doing the scheming (trying to have the Kettleblacks seduce Margaery). She obviously would make a good queen, as she is very open to the people and constantly gives Tommen advice on how to curry favor with the masses (something Joffrey was terrible at). She is very shrewd, as she recognizes that her arrest was all because of Cersei, and she knows the danger of the Ironborn invasion of the Shield Islands, but I still don't think she actually DOES anything in the books that would constitute genuine intrigue.
I think her position as a low strength character that is very good supporting others is extraordinarily nedly and, in my mind, she's one of the best designed characters, both in concept and in power level, in the entire core set.
One last note, I think Little Bird is an amazing name for that card. Look at Qyburn. He is universally hated in every single way when he arrives in King's Landing. And as far as intrigue goes, he doesn't seem to be all that good at it. He tries to curry favor with Jaime and the Lannisters by sending him Pia, the promiscuous servant at Harrenhal. He doesn't even know that Jaime is in love with his sister. Something that, by that time, was common knowledge among the common folk. Everyone he meets in King's Landing turns their nose up at him for his use of necromancy and experimenting on the living, many of whom don't regard him to be a maester at all. Yet once he gains control of Varys' little birds, he is able to not only secure the position as Master of Whisperers, but he even remains relevant after Cersei is arrested, almost entirely because he did have control of the Little Birds. Otherwise, you know he'd either be forced to flee or even arrested himself, considering the only person in the city that respected him was arrested.
If that doesn't scream "Gain an intrigue icon" I don't know what does haha.
I do find it odd how many things are considered conditions though. I guess that was a game mechanic to make condition removal relevant beyond Milk of the Poppy.