If we're talking about aftermarket style bushings...
The metal sleeve should be FIRMLY pressed against the sides of the shackle plates, The sleeve, bolt, and shackle should move as one unit. The bushing (properly lubed - they are grooved for a reason) should move inside the spring eye and the bushing should allow the metal sleeve to move inside.
There are two reasons the bushings even exist:
1) and most important, prevent metal-on-metal movement be physically isolating the parts.
2) absorb some shock and vibration from the road surface.
If we're talking about factory style bushings, I've honestly never seen them in person, and assume that they are a severe compromise in performance (range of motion) for price (soft rubber molded onto the sleeve?)