1. Stop saying that anyone is telling you how to play.
2. Stop saying that slider haters don't know how to use them.

You want a slider, good, I hope they give you one. My personal preference is, three or four difficulty options at the beginning of the game.

My major concern is that players and developers will try to use a slider as a workaround for a massive game flaw (horrible level scaling). Build the game right, no need for a slider. Go ahead and put a difficulty slider in the game, I will choose not to use it. But please don't use it as crutch or an excuse for an uneven or unplayable game. If the developers do their jobs, this discussion is moot.