Oh please. C is perfectly usable without knowing switch is actually a bunch of gotos. The idea that one has to know all the hidden edges of a language to use it is pointless, because every language has something like that. Even Python can be a minefield if one tries hard abusing metaclasses, and I'm pretty sure 95% of the Python users don't know how to use them.
If you pursue the idea of knowing every deep place to the extreme, the only language left for general developers to use is Go. A language so concerned at removing hidden features that almost no features are left.