Spirit and Opportunity were dropped from their "sky cranes" (yes, they had them too, but they weren't called sky cranes at the time) from several storeys up,
They had a rocket-powered descent stage, but it wasn't a "sky crane" because it didn't lower them on a cable, ala a crane, thus why it wasn't called one.
Yes. If anything, Curiosity had it easy. It was placed ever so gently on the surface.
Easier on the rover by design/necessity, though more complicated for the EDL team. Not ridiculously so like everyone thought, but definitely a source of complication and stress.
I didn't realize it when I was watching the EDL stream live, but later learned that they had agreed that, largely due to the public watching, they had to be careful how they called out the steps of the landing. Specifically they said "TD nominal" when telemetry said the wheels were on the ground rather than "Touch Down" because they didn't want to get the public excited when the next thing telemetry told them could have been that Curiosity was being dragged across the surface of Mars by the descent stage after a failure to release the cables. They waited until they were sure Curiosity wasn't moving before declaring "Touch Down Confirmed."
Oh man, still gets me a little thinking about those words. Hehe.