Loren the GM
Adventurer
The 5e rules are not great for heists. They have hinted that the book contains some more heist-friendly rules. If those rules are actually good, then I might be interested. But until reviews are out, I have no idea if that is the case.
I've run heist encounters in 5e and they can go really well. I'd say at this point 5e doesn't have official heist rules, so it isn't exactly surprising that the system isn't great as stands for heists, unless the DM makes it happen. As it currently stands, without DM intervention, a heist often boils down to lots of planning that quickly goes WAY off the rails (often into large amounts of combat) ending the "heist" early and defaulting back to a form of dungeon crawling..I don't know about that. Add a mechanic for doing Oceans 11-style flashbacks, have someone other than paladins in your heist team, and you're pretty good to go. I have a lot of rogues in the groups I DM for, and it's worked well for us.
What challenges are you encountering?
I'd love for the heist book to create some heist systems. Blades in the Dark could offer some guidance on how to handle a heist and make it more cinematic and player friendly. Plans, Loadouts, Flashbacks are great tools for a DM to use. I could see coupling that with something like the 4e Skill Challenge mechanic and creating a very nice, elegant 5e heist system.