Honestly, killing a dragon as a stealth character would not seem very epic as you're not really all up in it's face in the heat of the battle; you're just sitting back shooting an arrow or sneaking up and stabbing him in his scaled back.
I mean, in Oblivion when I had to kill important NPCs as a stealth dude, I'd just be in shadows, raise meh bow, and shoot. Guy might live, so you get another shot, then dead. You just didn't get this epic HOLY S... feeling for killing this dude, you didn't even make a connection with him/her. Sometimes you didn't even know it was a boss until you go over his corpse.
This was one of the main reasons on why I won't make a stealth character in my first run through the game. I want to feel the intense epicness of dragon battles. Your opinion may differ from mine though.