That is easy, it is Elder Scrolls V and all vanilla versions of Elder Scrolls were crap (well Morrowind was not that bad, but still no rpg masterpiece).
Morrowind not a masterpiece, you cant be serious. You didnt play it for long enough i think
Twas briliant, absolutely stunning. The atmosphere, the story, you could be whatever you wanted, in any faction you wanted, no quest markers, the rewarding feeling of exploration, the music and the great skill based leveling system that rewards every little thing you do not just combat, the great expansions, great community with plenty of mods. It repetaility is unmatched, you could literaly replay it 10+ times every time doing something different and finding new stuff.