Hi, there. Is your worry about occasional inattention/daydreaming the result of a problem in your life or a concern for being logical, perhaps rigidly so? There's nothing inherently wrong with daydreams, after all. I quite enjoy them =)
I believe honed analytical skills are an invaluable help in effectively decoding and navigating life and its problems. I do not think it a cure-all or a mark of godly abilities, despite the Ti-fetish many INFJs have because it is their tertiary function. But if you're asking whether such skills increase overall concentration, no, I don't think so; it just increases our awareness of details and subtly. We're all still human and are prone to the pull of imagination and wishfulness, an exploratory state of being upon which much happiness depends IMO.
I personally day-dream and let my mind wander on a daily basis because most of my insights come from such activities. As Ni-dominants, it's important to remember that our primary information processor is unconscious - it works best when allowed to disengage from our physical environment and its pressures. Only in solitary contemplation can Ni perform its trademark act of synthesizing massive amounts of information to generate novel perspectives and ideas. It's good to want to be connected to the world and what's going on, but do not cut yourself off from your natural mode of operation in doing so =) Such behaviors cause undue stress.
Do note, however, that concentration is affected by a multitude of factors, ranging from nutrition, sleep, exercise, stress and anxiety, interest, the perceived importance of whatever you're trying to concentrate on, and general motivation. Any and all of these things can contribute to concentration deficits.