Should they have a Trump character?
Someone who is from outside politics, very loud and aggressive, and has a kind of flamboyance about them? It seems they're trying to do that with Conway, especially with how contemptuous he seems of the voters in private (Which matches up to how Trump's detractors see him.), but I'd love to see Conway, or a new character, just become a complete loose canon who Frank can't necessarily plan around.
I mean, it's been remarkable how Trump has succeeded, when so many seasoned politicians have been trying to drag him down. And all on nothing but sheer personality. I don't really like the man or his politics, but from a narrative standpoint, he's fascinating.