So would you rather...
A) Have heists in a lobby like how missions are done right now (where other players can't interfere)
B) Have heists in a public/private lobby how store robberies are done
Here's my opinion, on it (feel free to disagree). I'm sort of mixed in this. R* said before launch that heists were going to be an experience where you can rob a bank, then share the money amongst the group. And if one of the group members weren't happy, he could shoot you in the back and take it all for himself. This is an interesting concept, and would be even more interesting if someone were robbing a bank, and then another group comes along (that wanted to rob the same bank) and then there's a gang shootout while at the same time cops are coming to help the bank. Also, it would be alot easier if there weren't loading screens so you don't have to enter and leave sessions.
The opposite can be said though, what if you were robbing a bank, and there's a big old tank waiting for you outside to make sure you can't have fun. Or if you rob a bank, and you and your member are celebrating how you just escaped the cops and meeting at checkpoint - only to have a buzzard start following you trying to shoot you down, and later holds a grudge for not letting him kill you and starts harassing you. Or right as your robbing the place - someone places a bounty on you + calls Merryweather. So many things could go wrong. Plus having a job lobby could make way for some awesome cutscenes which can't be done in a lobby with a bunch of players running around.