In my experience, what matters more than the size of the interface of the standard library, is its organization. For example, I can't really read Clojure code, mainly because I have no idea what the various functions do. On the other hand, Python has a huge standard library, but usually the name of the function, in the context of the module (as in urllib2.urlopen or json.loads) or the name of the method in the context of the class of the object it belongs to (e.g. [1, 3, 2].sort()) is enough to figure out what the functionality is.

Though I wish I didn't have to type `from datetime import datetime` all the time...