Git definitely doesn't fit the first approach. Not sure why you would state that.
Maybe the core of Clojure, with the persistent data structures, fits the first approach, but I doubt the rest of it does (speaking as an outsider to th eproject).
"Implement the best one" belies a lot of sweat and places where it could have gone wrong. In other words, the initial thinking is not even addressing half of the problem or doing half the work.
The philosophy of Clojure itself is very much based on iteration and interactive programming. You need a lot of action, feedback, and iteratino in addition to the "think very hard" part.