The basic concept of wearing clothes that are not overly loose is fine enough. I like being able to find clothes that fit passably off-the-rack, though I accept that I will always have to have sleeves taken up.
However, around here it too often leads to an obsession. Trousers must be razor-thin in the calf, even when a fuller cut has a fine pedigree--thin dandies like Fred Astaire and the Prince of Wales come to mind. Shirts must be darted even when they are plenty slim. I remember when one poster asked about tie width, the answer back was "Slim." Not "moderate," which everyone knows is the right answer, but "slim."
The emphasis on slim-fitting suits can also be a bit silly--a full chest and narrow waist looks more masculine than an all-over narrow. And pleats make sense, no matter what anyone says.
Clothes that fit are good, but it would do everyone here well to remember that there are plenty of correct ways to cut clothes, some of which are not borderline-tight and don't make your shoes look huge. And inasmuch as it means style giving way to fashion, I have my doubts about the slim-fitting trend.