There are many variations of 4-2-3-1 formation around the FM Community during FM16 time. I played with it too during first seasons with Akademisk Boldklub but I changed it to 4-1-4-1 after ten years in charge of the club.
It took some time when team played as I want. Especially some roles did not work and I tested it for more than one year when I was happy with that. One of the most important role is Wide Playmaker.