google search did have a killer UI though, you might be forgetting what search looked like before google
The technology was the killer. Technology providing the right list of results and fast.
OH and believe it or not, this continues to be the core of Google today - they suck at product design and marketing.
I feel like we are arguing semantics though. But IMO any UI that does the job that consumers want well is good UI. Just because it was simple doesn't mean it wasn't good