Moisés, if I caught your drift (if I am not mistaken about what you meant)...my advice is, variety is the spice of life.
And one (I mean you/me etc) have to strike a balance. You can alternate the two English areas (grammar vs flowing English "like it is").
There are some points more to add here:
--If a student try to learn something that is above his level, chances are that he gets tired and don´t learn it, try as him might. So, if he try harder and don´t understand something, he might go on what he also knows. He will mature in the future, and will learn in the right time.
--On the other hand, no pain, no gain. The above said, is no excuse to quit making effort to learn the simplest things.
--Even the ones that study using structures/drills etc, make a lot of repetitions.
So, repetition is a tool as well, but not mechanical rote learning, though. It have to be meaningful in some way. For instance, things that we like more we learn quickly, things/topics in which we make mistakes we learn more as well, and forget them less.
--We generally don´t learn much more, because we tend not to leave our comfort zone. To illustrate the point, nobody argue the subject/adjective inversion. Or discuss grammar when we say for instance "I love you", we are very very confident, but then we stop there...it may be a problem to many.
--Sometimes (or more often than not) the learner must understand his needs in English, for example, if he needs to go to Orlando (Disneyland) he doesn´t need to study as though he is going to sit a TOEFL. Just like a translator that is going to translate a Medical Journal doesn´t need to know everything about medicine. That´s why, there are translators dedicated to legal translations, others are into Business etc. A student should approach his learning needs, in a similar way.
These are just illustration points, I am not saying it´s your case. Others may relate to these, though.
Yet, the ones that experienced some drawbacks of those hardly will tell here.