I have to disagree with you, Sabeleye can Recover while most Ghosts have to settle for Pain Split if they even get that, and Sableye has 0 weaknesses. While offensively & defensively weaker than Spiritomb, it can W-o-w before being attacked so it takes less, something Spiritomb will usually not be able to do.
Sableye can also use Night Shade to hurt, and many people were surprised by a defensive Sableye set of :
Sabeleye: @ Leftovers
Prankster
252 HP/ 4 Def / 252 SpD
Calm
-W-o-w
-Recover
-Taunt
-Night Shade
Keep in mind, W-o-w helps make up for the lack of Defense investment, and Recover can help it stall out burn damage. Taunt is useful with priority and works against walls. Shadow Sneak and Sucker Punches wont be super effective vs this Sableye. And with priority, it needs 0 Speed investment, and it can always Taunt before Hitmontop or Donphan use Foresight or Oder Sleuth.