...I was still half under the impression that they would just computer generate Susi's voice because she was just a modern day ( but much funnier version) of Carlton (this is Carlton your doorman) from "Rhoda". Unseen, but still an important supporting character.
...The whole cast did a wonderful job. They even humanized Sheldon for five minutes.
Yes, putting that wisdom into Sheldon's mouth was inspired.
I thought one option would be just to keep recycling her comments from previous shows, in different contexts, but didn't think they'd actually do it. One funny possibility would be for Howard's long lost father to come back, and be exactly the same as her.
