Some Pros for me:
1. The improvement in how the environment interacts with the game. Basically, i love how everything doesbt just attack me, but everybody can fall victim to attacks by beasts, npcs, etc.
2. Dragons and their shouts. Very exciting and unqiue. The Signature of Skyrim in my opinion.
3. Graphics are better than previous ES games.
4. Skill tree/Perk tree system is a better edition to make a unquie character.
Some Cons:
1. Lack if spell variety. Especially the loss in being able to create your own staves, scrolls, and spells. Really limits a magic based character and less crafting versatility.
2. Lack of monster/enemy variety. Same monsters around every corner for me. Every camp has bandits, or every forest has just bears and packs of wolves.
I could name more, but i want to see what my fellow players think. Share your pro's and con's and feel free to comment on mine. (: