I haven't found a huge use for Skeletal Warrior. I don't deal death too often, and when I do, it'd have to be a pretty low many cap to spend a slot on such a weakling. Oftentimes, Cocatrice would be a better tank if you think they're not tossing magic.
Possible an interesting card for Up-Close-And-Personal, but then again, I usually need heavy hitters that can kill faster than a beefy monster heals.
Its all about that shield. Amplifies the damage he can take in a very meaningful way at higher levels.