Yes. Skyrim is far more of an RPG than The Witcher series. I would be interested to hear your reasons as to how it isn't?
Cos despite letting me customise my character, Skyrim never succeeded in making give two hoots about anything in the game, I therefore did not feel that I was playing a 'role' as such. Or if I did, then only a rather pointless and vapid role.
So I'm interested in getting the Witcher 3 but I haven't played the first 2. Without getting my head bitten off by die hard fans is it necessary?
For example for me I preferred Oblivion over Skyrim and if someone asked me I'd say hell yeah play Oblivion, but it's not a requirement before playing Skyrim. Or is it more like Mass Effect in regards to the story?
As others have said, playing the other two isn't necessary although it is good to have a bit of background in the lore and story. As entertaining as the first game was at the time (I never finished it though), there are lots of annoying things about it that a modern gamer and/or a more action orientated gamer might not tolerate. For one, Witcher 1 still has one foot in the turn based point n click side of the RPG fence. There are about a dozen character faces which you will see time and time again, all the building interiors are a bit crap and repetitive. Also Witcher 1 is definitely a game that must be played with keyboard n mouse. Sitting back in an armchair with a gamepad would be totally out the question for this game.
Witcher 2 however, is a masterpiece, and it would be a great shame if you were to miss this title simply because you chose to play the Witcher 3 first. I played through the Witcher 2 twice, and each time, was a totally different game, due to me purposely making different choices each time. Think there is something like 32 different paths that a gamer can take through the Witcher 2 in total.
Great game, stunning visuals, great characters, dialogue, story, fun combat as well (better combat than TW3 imo). Only gripe is that it isn't 'open world', with invisible barriers a plenty (which is something I hate).
Get the Witcher 2, play it through, and then import your save game into Witcher 3 (choices you made in 2 will affect events in 3).
That there will be at least a couple of hundred hours of grade A story driven RPG gaming that cannot be matched by any other title.