Things go wrong, heists get scuttered, if they were easy then everyone would join in. Shadowrun's mechanics as the example seem to require some streamlining to reduce play fatigue from game prep, I wouldn't dispute that, but it seemed like you're seeking mechanics that can guarantee the favourable outcome of any heist for the players pulling it off. "Just in time" flashbacks suggests that.
If you just want a fast way to enjoy some escapism, a board game would be much simpler to design with way less overhead, as that would focus strictly on the heist and no other elements. If you desperately need more features, like political intrigues, make some expansions.
I think you should play some BitD! Scores go wrong all the time. I mean, if you play well, you will probably succeed on a hefty majority of them, like you would on most D&D fights. However, in BitD when you attempt to act, you get a 'position', either Controlled, Risky, or Desperate based on the fictional situation and which action rating (skill) the player chose to invoke (they will have had to describe appropriate fiction, but in BitD the choice is theirs). If its wildly inappropriate, its probably desperate even if the situation isn't THAT crazy, etc. Now you roll your dice. Should the results come up 4 or 5, you succeed but something happens. How bad that is depends on the position, so you could suffer some harm, a complication, or reduced effect. On a 1-3 the consequences are more harsh, but similar.
Harm is pretty nasty in Blades, you don't have 'hit points', severe harm is 'level 3', you cannot function on your own without help for the rest of the score! normal harm is level 2, you can get this twice and it cuts your dice pool by -1d per instance (usually not on ALL checks, the GM will describe the type of harm). If you have 2 level 2s and you get another one, it bubbles to level 3! Level 1 reduces your effect when you get success (4-6). Again, probably not in ALL situations, and you can get this twice also, the 3rd time bubbles up to level 2. Should you have the misfortune to get level 3 harm in a situation where you either already have it, or the degree of harm is increased (something REALLY nasty hit you), then you get level 4 harm, DEAD.
You also have a stress track. You can 'resist' bad consequences (like harm) which gives you a fortune roll (usually 3 or 4 dice, maybe 5 sometimes). 6 - whatever you rolled is how much stress you take for resisting the consequence down one level. You only have 9 stress starting out, so this can be rather risky! Once your stress hits 9 you are 'stressed out' of the score, and you suffer trauma (some kind of permanent effect). 4 traumas EVER removes you from play (you can get a 5th trauma box as a special ability). There is no way to remove trauma.
Stress is also required to 'do stuff', like a flashback may cost 1 or even 2 stress if you are stretching things a bit to call for it. You can spend 2 stress to 'push' your character (add 1d to a dice pool) as well. There may be other ways to use stress as well, depending on your abilities.
The upshot is, its not AT ALL true that you 'always succeed', and my character has failed a couple of scores and been stressed out a couple times. In fact I failed a score a couple sessions ago where I was NOT stressed out, but I had so few options left, both mechanically and fictionally, that it was just clearly impossible to succeed. I ended up 'closing out' the situation in a way that wasn't ENTIRELY unsatisfactory, but which was not fictionally how my character wanted it to go (he killed a guy whom he was once friends with). So it goes in Doskvol!
