[Skylled]

I'd think there would have to be something fundamentally different. It would have to be hardly recognizable as a "search engine."

There's too many clones on the market right now. Some with good purpose, like DuckDuckGo which can be simplified to "Google but without privacy invasion." Others like Bing could be just "Google but clunkier." (my opinion)

If you've got an idea on your hands that can't be described as "Google but..." then there's definitely room for another.