Focusing only, or mostly, on formal structure always[0] seemed to me to be just a failure of teacher at introspection. For instance when using your native language, if you stop and look at your own thought process, you'll quickly realize that you don't consciously invoke any grammar rules. In fact, the brain doesn't have enough computing power to explicitly build sentences by applying grammar rules, not if you want to have a conversation. It should be obvious, on introspection, that formal structure can be only a scaffolding for building your cache.

[0] - For things you learn to use all the time, or to leverage your cognitive process. The obvious exceptions are things you want to do with mindless precision, where the risk of guessing wrong is unacceptable. Compare public speaking to memorizing a poem, or guesstimating to doing explicit pen and paper arithmetics.