Trust me,im no fan of World of Warcraft games too. Actually WoW fits in another genre called MMORPG.I was kinda like you though,I used to play Kingdom hearts as the only role-playing game back in the day,But when I tried Oblivion it was a whole lot different kind of role-playing game with more open-ness,a huge world,and many quests.Yo can do whatever you want,actually you can even decide on skipping the main story and just roam through the vast map and finish side quests.Even though I like JRPG's,but they're usually linear and have a strict line that you should follow,but not The Elder scrolls games.
I sound like an advertiser
,but seriously you should give the game at least a try....you'll jut fall in love with it.
And to answer your last question,No,you don't need to play the older games to understand anything,It is a whole new story.Although there are a few hints to the old games (because the events of the past games happened in the same world but in different areas) but they shouldn't be of any importance.To make it better,I haven't played any of the games before Oblivion and I understood the whole story.