Daggerfall is a classic, and while it may be less accessible than recent installments it is arguably the most ambitious.
Story-wise, Daggerfall's exploration into the themes of integrity and loyalty through the tale of complicated political strife ridden with backstabbing, shameless grabs for power, and subterfuge sticks to the franchise's fantasy roots while also portraying a very realistic situation. While the cast is colorful, it is also fairly flat. Mannimarco is ambitious. Elysana is ruthless. Eadwyre's a jerk. Mostly everyone is unique but not really explored (a couple exceptions may be Barenziah--who is only given a deeper character through the game's books--and Mynisera). The generic dialogue is as awkward as any other Bethesda game, and sometimes it just doesn't make sense (ask the king of necromancers about necromancers--or himself for that matter--and he'll usually say something like "Never heard of them").
The gameplay is complicated--which is both a good thing and bad thing. At its good points it's challenging and varied. Reputation was a great facet to the game and worked wonderfully with the central themes. The dungeon diving is terrible. It's perhaps not so bad if there's no quest involved, but if there is you'd better pray that the target is right around the corner or you might spend a whole real time day never finding it. While some of the main quest dungeons can be breathtaking at times (the rows of statues at the entrance of Lysandus's Tomb or the final dungeon), good luck getting through them without a guide. Some gameplay mechanics sounded good conceptually (and might have been great in later installments) but often had had no use, while others are totally necessary and broken (like swimming). The actor for the emperor at the beginning did a great job (not Patrick Stewart great, but still fairly impressive) while the voice acting for other cutscenes is unintelligible and sloppy, which is incredibly disappointing when you've just beaten an incredibly difficult game and can't hear the ending.
All of those things might be complaints about how old the game is, but ultimately there's a reason it's stuck around so long. While the newer installments have touched up the gameplay of the series to be more accessible, there's a charm in Daggerfall that can't be found anywhere else and experience like no other.