To put it simply, I hated it. When I joined the Thieves Guild, I expected to have to steal something. I didn't expect that half the quests assigned called for absolutely no thievery. Rather, I was asked to crawl through dungeons in the service of some bland and easily forgotten deity; but then again, none of the other characters managed to interest me. Maven Black-Briar was compelling enough. I would have liked to see her personality developed. Again and again I was told that the Guild was in her pocket. In practice, however, her influence is almost nonexistent. The Dark Brotherhood quests were pitch-perfect. The Thieves Guild was uninspired. (By the way, I apologize for any spoilers. I haven't been on this website since New Vegas was released, and I was unable to find the tag).

There's plenty of "theiving" quests when you get done with the story quests. You have to do 5 radient quests in each of the 5 cities... randomly. The minimal number is 25, but it works out to be closer to 50, in order to become guildmaster.

If you want to restore the Thieves Guild to its former glory like you are supposed to and HAVE to if you want to become guild master you'll have to do plenty of side jobs that are all based around thieving... You have to do a minimum of 20 of these since you have to restore the guild's foothold in the 4 other major holds, the foothold in Riften is taken care of by simply following the main Thieves Guild quest line though you will still receive side jobs for the city... If you quit jobs to only do the ones for the cities you haven't still restored then you will be able to do it with only 20 quests plus another 4 for the actual quest to restore the foothold in that hold... Be warned though that every quest you quit will reduce your number of completed quests by one... Mine is at -17 because I didn't want to steal from Riften and they kept handing me quests for Riften over and over... The quest line does make sense so I don't complain too much...

Go here and steal that is routine and you get those from the side/ radiant quests. The Nightingale story line uses stealth mechanics in other ways and uses shadow and luck as metaphors. It's more unique than some big heist. I can see down sides to the metaphysical angle- you're forced to make a daedric pact or not advance- but at least it's creative.