Ingame, there was already a destroy the DB quest.
Wonder if a modder could make a similar quest to flush Maven and those thieves guild + nightingales out of their 'flagged-ragon'.

That would be a cool mod suprised Beth did not come up with one (was suprised on the destroy the DB in vanilla)

It would be nice. Or, once you become guild master of the thieves guild, you should be able to take out Maven so you own the town, not her.

i want a competitor guild. but like playable. when i first started playing i thought the nightengales were competitors of the thieves guild like the camona tong were. boy was i surprised....and slightly let down.
i felt the whole quest line to be a little too magical. not "thief" enough for me.

i wanted some huge heists in some old mansion somewhere.

This is a big desire for me as well, I'd love to take out the Thieves Guild with Mjoll, infiltrate it from within and destroy it that way or from without. As it is my character just stays away, with Brynjolf's quest forever stuck in my quest log I feel like this is something Bethesda should have done, and should make a DLC of, but I seriously doubt they will. They rarely (if ever?) touch vanilla content with DLC.

I get the feeling Bethesda wanted to have a quest where the player could do exactly that. The castle steward suggests that he wants to destroy the guild as well, by taking some guards into the sewers. It's a shame it didn't make it into the final game.

Just needs a little bit of elbow grease though!

When I first met Mjoll I really thought taking down the thieves guild was going to be an option. The talking to the captain of the guard I thought maybe here where was the quest would materialize. I was rather disappointed .