There isn't a particular game that I love. I picked Skyrim becuase ni one else did.
Pros:
You are allowed to be who you want. Compare to Baulders Gate, Witcher or Dragon Age - you have to role play a type of character. In Elder Scrolls, you can easily transfer between warrior, mage or thief. Or you can be all three at the same time leading to a lot of interesting gameplay
Modular design to open world. You can explore in any direction. You aren't punished. Compare to Fallout NV where you are forced to go a certain way and are punished for stepping outside the rails.
You can use spells, weapons and shield at the same time and it is easy to change up your tactics.
The various major factions have a long history together and they have very strong motivations.
Your choices matter. The diplomatic mission Season Unending has so many ways that it can turn out depending on a lot of choices. Unlike any other game, these very disparate groups put aside hire difference to achieve a common goal.
Subtle storytelling. Places like Rorikstead or Winterhold come to mind.
The console commands can fix any problems.
There are lots of cities that has lots to do.
Massive quests like the crown of Benezariah or the Dragon Priest masks
Cons
You can't be who you want to be. You are stopped from killing people who are relevant to quests. Daggerfall had you randomly failing quests becuase you killed someone randomly 40 hrs earlier. Morrowind said you'd break the prophecy (which was the most egregious. How do you know so much about this prophecy that you can tell whose important to fulfil on it? But you don't know the word Nevarine.) All three are bad, and I don't know a game that has fixed his problem.
Modular design. Everything feels unconnected. There aren't specific areas that are challenging and you have to come back to.
Spells are not epic. Becuase the damage has to be compared to a weapon, they are toned down. You don't get to build your own (but the game isn't broken by your spell creation so that good)
Minor factions are uninteresting.
Your choices don't matter. No one from the game helps you with the final battle becuase you aided them earlier. When you finish a quest, they don't change anything on the map. (For example, picking a side in the civil doesn't change much about that city except it gets rid of a leader)
A greater portion of the story telling feels like they are using a hammer instead of a chisel
That there is a need for console commands I.e. To fix bugs.
There are hardly any villages and The Pale seems really undeveloped.
A lot of repetitiveness. But then I thought Witcher 3 was really repetative
There's more but I've had enough