What if they had a secret organisation or two with (a) base(s) in various cities? Like perhaps the thieves guild meets up in the sewers and uses various exits to get to places where they can take things and not be caught, like entrances to basemants or something?

It would be a lot better than meeting by some houses or whatnot. Actually, if the TG was based out of the IC Sewers in Oblivion it would have been really cool due to the sheer number of buildings you could break into from there. You have access to almost all of the IC. Plus they could have easily tunneled up into the Grey Fox's house

you mean like how the Dark Brotherhood was located underground in Cheydinhal? I am guessing you mean tho that entering the sanctuary would lose anybody following you and that there would be a couple of such bases?

Uh yeah, I forgot about that. Was mainly thinking about sewers. Just a cool place to have a secret organisation.

Hopefully, more of the darker guilds like the Thieve Guild and the Dark Brotherhood/Morag Tong make their base in the sewers under the major cities. While the sewers need not entrance/exit to every single home, it does need multiple entrances/exits, and winding passages. They could also take advantage of condemned buildings like the Dark Brotherhood did in Oblivion.

What I'd like to see is these guilds use different building types as their meeting place. Something I'd really like to see, and hope for, is that buildings that are condemned or ruined are left there, untouched, and a mistake on the city official's part. Like a chapel in a rebel-dominated city that is closed would be used as a Dark Brotherhood base of operations, in a ironic twist. The Thieves Guild will make bases in rich districts, the most unlikely places for anyone to look. Or, these guilds could make bases in dungeons outside of a city.

Anyways, I hope we see multiple bases of operations. I don't really play for immersion, but as widespread as the Dark Brotherhood is, there shouldn't be just *one* base that the player can reach and accept quests from. In Oblivion, there were multiple chapters of the Mage and Fighter's Guild, but really only one Thieves and Dark Brotherhood headquarters. There were many supposed Dark Brotherhood Sancturaries mentioned as well.

I agree with your idea Dragonbone, hopefully we'll see the secretive organizations use more underground hideouts.

The Mythic Dawn used a Sewer base too, but yes, it would be nice if a secret organization could have like sewer hide-outs, not main bases. It's very unlikely an organization would have a main base underground in the sewers in reality, but a smaller hide out where a few secret meetings or fences appear at would be nice. That said, the thieves guild recruitment Doyen just being outside between some buildings was fairly unrealistic too... an underground hideout or small base is fine, I doubt any organization would ever set-up entirely in a sewer tho... I'd prefer the Dark Brotherhood's secret wells as a more suitable place, since it's both underground, and not a place that'd really stink out any would be organizations.

Actually what has come to mind as a nice possibility for a thieves guild would also be the basemant of a tavern or an inn with the tavern or inn acting as a front for the more illicit activities below, perhaps instead of then having the hide out in the sewers, that basemant could have access to and be accessed via the sewers.