lets see, magical minions, magic traps, bottleneck corridors made for maximum dragon breath burnage, almost unavoidable magic alarms design to wake the dragon, oh and a sleeping area designed so the dragon can sleep with only his hard, almost impenetrable scales exposed.
Wait..! So are you telling me its a near impossible situation, full of obstacles that one must use logic, skill, and pure luck to get by, in order to achieve the most epic throat slit in the game? And this is not epic how? Does this not strike you as maybe being exactly what Stealth characters are about? Such impossible odds are our specialty, why we create our characters, and that is where our heroic acts are.
This. The whole point of a stealth character is to sneak in, dodge the traps, kill the target and walk back out. While I doubt dragon lairs are in game, this aspect would truly be awesome.
But how to kill one when it's out and about? Maybe wound it, hide and follow it's to it's lair whiole itt's recovering?