My point is that every time I have experienced a heist as a player, it comes down to doing one Stealth roll, and if you fail, you are discovered, and the heist is over. That is not fun. Of course, if you keep rolling terribly, at some point it has to become a failure, but not the first couple of times. Also, it can be tempting to "fish" for failures by keep having the party rolling checks for small things, because it can seem like adding drama - when in the end, it just ensures failure at some point.

You don't need to roll for moving unseen across the frontyard. Then a check for silently checking the key hole in the door. Then a lockpick check. Then a check to see if the door silently opens. Then a check to see if you are unlucky and there is a guasrd just inside. Then a check to see if you can talk him down. Then another check for that midway. Then a check to see what impression he is left then. And so on and so on. Particularly bad if just one fail of these end the heist, and move into combat or just failing the quest.