PC is ALWAYS king. So much so that PC has to be given a nerf (aim assist) to allow the console plebs to even be given a chance at comparing. The problem there though is the aim assist REALLY makes a difference and gives them too much of an advantage. If your mainstay is RPG then COD won't appeal too much. The campaign is a lot of fun, but otherwise it is a twitch 1st person shooter.
RPG wise you have The Witcher, Skyrim, Star Wars KOTR, and Fallout are all titles I have not played, but have heard from friends that loved them a lot.
Ones I have played and can vouch for include:
Deus Ex (played the series and loved the whole story and gameplay)
Mass Effect (fucking amazing game play and story, they really did a great job with this one...except Andromeda.. leave that piece of shit alone)
Dude. Fallout. WHATTTTTTTTTTTTTTTTTTTT