There's no incentive to simply wander around killing everything. The game centers on your 'crew' and its relationship to other factions (not exclusively, but this is a major theme). Wandering around murdering everything will simply get you annihilated. In that sense BitD is much more realistic than most trad D&D I've played. You are part of a society, and if you don't act within your space within that society, it will get rid of you.
The game doesn't center on 'heists'. You can do something like a heist, yes, but scores are not heists, they're 'action time', a focused sort of mission part of play where the PCs do stuff related to their themes and interests with a specific goal and encountering danger. Your crew could be assassins, thieves, dealers, smugglers, revolutionaries, etc. Basically the crew is always on the 'wrong side of the tracks', and thus considered 'criminals', but you have wide latitude in terms of what that means. It is also pretty flexible, and crews seem to IME evolve or grow into a unique form.
As for flashbacks, you can use them as much as you want, but IME they weren't something that was needed constantly. First of all, you have the ability to pull different things out of your 'gear' without really needing a flashback. Much of the time you can use generic items you own "yeah, I did bring the crowbar." Sometimes you do a flashback, "Oh, after we learned about the guardian spirits (during info gathering before the score) we create a special ward against them." I've no idea what is 'wrong' with that, it is simply highlighting that your characters are darn good at what they do.
Obviously BitD is a specific game, intended to provide a certain kind of play in a certain genre and milieu. Nevertheless this system has seen a pretty good amount of adaptation, though most of the ones I've seen parallel BitD to a degree (there's a group, and that group is outside the normal power structure, and there are complex allegiances with other groups/factions/powers). I'm sure someone can point out games which break this mold, I'm no great expert. It is a very solid game, and the position/effect resolution system is pretty sweet in play.
