1. So? During the course of Skyrim I can play several different characters.
2. So? Leveling up and weapons/weapon damage have nothing to do with Skyrim's campaign either from the sense that they don't affect how the story plays out. Besides, you can't take just the Black Ops single player and compare it to Skyrim, we're talking about each game in its entirety.
3. People say this about Skyrim's story.
LOL okay. You level up by using your 'skills'. By using your 'AK-47' skill you level up quicker because it gets you more experience by completing challenges and unlocking attachments. As you level up your 'AK-47' skill you get better at using AK-47s by getting a grip to make firing more accurate, or sights to make you shoot better. Both games also have 'Perks'. Plus, CoD: Black Ops has a lot of character customization - you can choose your facepaint, and have a very limited selection of clothing to wear, just like in Skyrim.
Need anymore?

CoD is not an RPG, and cannot be considered even close to as such because:
-The "leveling" has no bearing on a character, you are simply acquiring unlocks for things.
-There is no "character", the definitive basis for "roleplaying". Playing a "soldier" is -not- roleplaying. You don't make choices for, and develop, a character.
Skyrim
is an RPG because, whether you believe it's deep or shallow, you make choices to develop your character and determine his path. You determine how the character develops via choices in skills to define who that character is. You make choices for that character within the world to determine their personality (and yes, contrary to hyperbole belief around here, there
is choice in Skyrim, quite possibly more than in an Elder Scrolls game previously). You are actively in the role of a character, and acting as that character - the very definition of roleplaying. You are making character choices for that character within the context of a world - the very definition of roleplaying.
It is no less of an RPG because there is no Intelligence attribute, or because some glitchy dialogue has a guard calling you the new College recruit when you've become the archmage.