Picture a mod where you can turn blackreach into a city like whiterun, but you have to build everything like hearthfire and you can become thane of that hold as well along with a house and housecarl for you.

Things to be done would to be to kill everything in blackreach, maybe find a way to make the machines friendly and act like addiontal guards ontop of the guards you'd already have. maybe people from this site could voice some of the shop keepers or guards or whomever?

ontop of this maybe a third side to the war of dragon priest faction where draugr, dragons, and dragon priests are friendly and may help with defence? O maybe this could be a new guild?

What do you say? (this is an idea as i have no knowledge on how to actually do this)

Im not a very serious modder; Ive made a quest/faction/playerhome/craftable item, and only one of each. However, Ill take a stab at it and break it down:

Turn Blackreach Into A City (but you have to build everything like Hearthfire): Hard. However, this could be done by me, sort of. It would take forever to clutter, and my current scripting skills are nowhere near good enough to make it piece-by-piece buildable, but a replacer would be easy enough. At a compromise, you could have a few activators or wait timers to simulate rebuilding it. This...would still be pretty far out of my range though not impossible.

Become Thane of that (city)  along with a house and Housecarl for you: Doable. There arent any requirements for thane, but lets assume its a quest where you do a fetch quest and a bounty, easy enough. You then get the key to a house with a follower inside. Easy peasy.

(Snipped for size, the part about killing things, hiring guards, voice acting): Kinda falls in a weird area. There...isnt much do to  here, really. Maybe two or three quests to clear an area, but that would just be fluffy filler to add more action.

Ontop of this maybe a third side to the war of Dragon Priest faction where draugr, dragons, and Dragon Priests are friendly and help with defence? Or maybe this could be a new guild: Again, it falls in a weird area. This could be done, but it just wouldn't...fit, if that makes sense. It may sound cool on paper, but its execution would most certainly be botched and halfhearted.

 Again, I'm nowhere near an expert modder. Probably not even an experienced one! But nevertheless, this sounds within the limitations of Skyrim, it would just take a small team or a very experienced modder. Cheers