They are both brilliant games.
The witcher 2 has you taking on the role of an already fleshed out character, and you are playing out a tight storyline.. what you do inbetween is fair game, the release had it's issues (UI issues remember... felt like the game was designed with consoles in mind) but still was highly optimised for PC's.. I played it through once, on hard.. and loved the experience

Skyrim is an open rpg, but still has a very linear story 'IF' you wish to follow it, it's the freedom of choice that players love.. though it can be broken easily. (become archmage.. get told to apply to college of magic repeatedly by npc's) Game has it's issues on release.. annoying UI, buggy quests and poor performance but the good outshines the bad.. it's an astounding game.
Basically, don't hate on rpg's.. they can be done in many different styles and flavours.. at the end of the day if you are interested in hearing a good story, a good rpg is something you want to sink your teeth into.. we get so few decent rpg's these days lets not bash the ones we DO get to hard eh
