Those GMs who want to run Intrigue games, then I suggest you watch Kings, amongst the many great inspiration sources for a campaign like Rome. Since the show is in decline, It actually makes for a good framework to base a Political Web structure for a game and with the advantage that few people are watching it.
I admit that I'm more for a Rome Kind of Intrigue, but Kings is simpler and easier to work into a classic medieval game. A GM does not need a complicated plot, he needs a one that will work with the PCs and flesh out the world and fun. I'm a GM who used to pour so much detail in NPCs, but Players don't see those details. Not many Players are into that thing, but the GM is and it makes the whole game much more "creative" to him who spun it.
I'll try to break it down to Templates and Substitutable Elements in my notes, and see If I can organize it in a nice enough way that GMs can just grab the structure and replace-place their own elements in the slots. The thing about plots is that, a well conceived one is simple and elegant. This makes eases the GM's job cause he doesnt need to lead the PCs, they make their own way and lets their cleverness shine. Like in any Project, the GM takes the role of nature and adjudicates if certain risks pan out or not as part of the "adventure" part.