Now, what happens regarding the Forsworn, is that you enter Markarth, do the quests The Forsworn Conspiracy and No One Escapes Cidhna Mine, and then that's it. Perhaps the Jarl will give you the task to kill a Forsworn leader somewhere, but even those leaders are just normal, leveled Forsworn.
Why is this? The Forsworn are so much more interesting than the bandits that roam Skyrim. They have something to fight for, a motive. It's almost as if Bethesda made the game with the intention to do something with the Forsworn, but decided not to in the end. Hell, The Reach is full of Forsworn hideouts that are almost as impressive as Markarth itself. Deepwood Redoubt is even equipped as well as your average city - the forge is there, the alchemy table is there, the workbench is there. All we need is some more depth and possibilities with the Forsworn to really make The Reach come alive.
As it stands now, nothing you do in the two aforementioned quests changes anything regarding the Forsworn. This should change, and more quests and interactions could be done with the Forsworn. Perhaps the Forsworn could even be a joinable faction of their own - there are so many possibilities that are just disregarded altogether. What a waste.
What is your stance on this? Would you like to see more Forsworn interaction, or would you rather just see them all rotting in Cidhna Mine? Come to think of it, that may also be the outcome of a new Forsworn quest. Yet another missed chance.