I don't like the disappearance of the sliders.
It would make good sense to change the ones in the modern tactic that still remained for the team instructions: defensive line, width and such, so as to allow the player to not see them. But I really liked to have them available as an option to work with. Whoever didn't want sliders just had to avoid clicking the buttons to show them and to not convert to classic. I don't see the need to avoid the sliders to those who would choose to play by them. Unless changes to the tactic engine have been such that the sliders stopped being workable, which I doubt as it didn't sound it was that why they removed them.
Still, the new way sounds potentially interesting, though I didn't pause to have a closer look to see if the choices are too few. Initial impression is that they may or may not be few. We'll see once the beta/demo comes out; but I do look forward to it. I will miss the sliders but I won't cry over the loss. Unless the new system is very poor, which I doubt.