On their own as just burglars, they aren't my thing but I would have interest if they were added in a way that allows the player to decide if the game tilts entirely to the bad side or if there are consequences for crime. I would want to be able to punish or reform them if I as the player want to do so, I get that some other players wouldn't be interested in that but it would be important for me.
I would have interest in some sort of glamorous heist pack or if they add more gameplay for museums (needed) or if they expand the archaeology along with it. Find more objects with optional good and bad characters. Add more types of art and more activities for artists and museums but also add burglars and heists or capers.
I think some players want to play in a bleak crime world, fine, I think they should be able to do that. I don't but I do have some villains or complicated sims in my game. I've already had a few criminals in my game. I could see playing with some more playable burglars but let us send them to the jails. I know we already have detectives but I'd want some sort of inspector to be able to pursue any burglars. That's a classic type of gameplay with nods to the past.