I didn't play Daggerfall. What were the guilds like in that game?
They were more like actual factions. There were no plots or questlines, just quests... infinite, randomly-generated quests. Those did indeed get boring, but that's why I would like to propose that Skyrim, with its own form of random quests (radiant story), combine hand-crafted plotlines and infinite quests for guild work. In Daggerfall, performance actually made a dent on one's ranking within a guild/other faction. The player character would have a reputation with each faction and reputation points were gained for successfully completing a quest while a lesser amount of points were taken away for failing. The player character had, in order to be promoted, to have a high enough reputation, high enough specific skills (there was flexibility here), and they had to have not been promoted in the past in-game month (they passed by quickly in Daggerfall).
I believe the player character can also be stripped of a rank if they show lackluster performance (based on reputation), but I'm not entirely sure on that one (never happened to me). The player character could never rise entirely to the top of a faction, although they could be of considerably high rank, and the factions always felt like actual, large, powerful factions rather than little clubs that could just be taken control of. With higher ranks came more privelages and some nice rewards. There was always more work to do with randomly-generated quests. Again, they did indeed get repetitive, but combined with plots, I feel as though they could assist in keeping factions feeling like factions. What kind of Fighter's Guild permanently runs out of work for its members, for example?