That's strange, pmmg. For me it's rather the opposite. In earlier efforts I was painfully aware of the writing itself and struggled mightily. Lately, though this happens only in unpredictable ways, I write the story and not the words. That is, my attention is almost wholly on attending to the details of the scene--the tone of dialog, a feel for back-and-forth and talking at cross-purposes, calling in bits of description, even moving through action scenes--and the words come readily to hand.I want this back too. I used to produce so much more before I became 'good' at it.
The best analogy I can think of his playing guitar. As a novice, I was painfully aware of which string to pluck or how to place my fingers to make the next chord. With practice, that stuff came naturally, without conscious thought, even to the point of moving at the right time from a major to a minor seventh or some such. It flowed as easy as talking. I put the guitar aside for many years (fell in love with midi keyboards and sequencing). When I returned, that old clumsiness was back.