Squad-based Heist Game

Background: There was a top-down 2D stealth action game I loved called Monaco: What's Yours Is Mine that I spent hours and hours on. The goal was to steal stuff, get past guards, all that good stuff except the fun part was that there were different characters to choose from each with a heist-themed special ability. One person was better and opening locks, one person could disguise themselves for a short time, one could knock people out if they came from the back. This also reminded me of one of my favorite shows bar none: Leverage, a group of thieves with Robin Hood morality who each have a special skill: one person is the hacker, one person the actor/"grifter", one person is the combat specialist, one the cat burgalar and one the mastermind. One of the games I would love to play one day, and may need to make to do so, is a 3D stealth action game in which getting in and out, with mission objectives closer to those of, say, Mirror's Edge, is the thing. There was a game that had a very similar theme to what I'd like, it was called PayDay 2, however the gameplay was very much like a first person shooter, with the themed heist mechanics treated much like perks are in other FPS games. I would prefer something more like an Assassin's Creed in terms of camera and controls.

Title: Heistworthy
Genre: Stealth Action RPG
Players: 1-4 Player Co-Op; 1 v 4 player assymetric play.

This game will have a typical stealth gameplay loop: Observe obstacles, plan a strategy, excute, run into static which escaletes suspicion, hide and take action to subdue suspicion, repeat. Each mission or 'heist' will center around retrieiving an object and escaping with that thing.

Classes:
All players would have basic abilities to pick pockets and do sleight of hand, as career theives, as well as wear disguises, use keys and keycards, and answer basic questions correctly when approached by NPCs at the heist location. The available classes for your visually customizable character would be as follows:

Hacker
- The environmental mastery class. Using a hacking minigame, the "Tech" is able to access cameras, digital controls and computer data, including NPC schedules and profiles for keys on how to avoid and manipulate them. They are able to highlight useful information for their teammates. They balance getting closer to get better access against being further away to stay safer.

Fighter
- The combat stealth class. Using tried and true stealth combat mechanics, plays most like Hitman and clears NPCs that are otherwise very difficult to deal with, and then must hide the bodies. They balance high reward of taking out an NPC to the high risk of being seen, and because seeing them act draws such large suspicion, they are essentially a glass canon in RPG terms.

Infiltrator
- The social stealth class, a master of disguise. The infiltrator's disguises are more effective and they are able to have full branching conversations with NPCs in order to gain information and access. Is able to move most freely and gains suspicion most slowly and loses it most quickly. They are, in a way, the tank of the team.

Taker
- The thief class. This class represents the lifelong thief, who is much faster and more effective with the basic skills available to everyone: pickpocketing more quickly with less suspicion, a larger slight of hand inventory and and quicker with lockpicking and safecracking than teammates.

Maker
- The crafting class, making items for the team. Some of the more complicated devices, including forged documents, advanced safe-crackers, explosives and drills require them to be on hand to operate those devices, which they must maintain. Their function is not only to create the needed items, but to ensure the getaway plan in place.

Thinker
- The leader class. This class is able to see their teammates' actions, and can direct them by creating waypoints, which provide buffs to the actions the thinker sets for those waypoints. They also have the ability to unlock buffed versions of moves in their teammates. In this way, the thinker 'leads' his team with buffs, some more complicated than others.

Missions:
Heists themselves come in different tiers and players advance their abilities and become acquainted with more advanced tactics.
Tier 1, Basic: Breaking into a single room or warehouse or small bank branch is easy, sometimes a 1-man job.
Tier 2, Hijacks: Taking moving objects can be more difficult, especially if there is a caravan, but good planning can make it easier.
Tier 3, Security and Socialization: Such as mansion parties, clubs, and concerts all involved hired security guards and a lot of eyes and bodies, which can be both helpful, and not.
Tier 4, Guarded Buildings: Low level government facilities, hospitals, and other well secured places of protected business house lots of great documents and unique resources. Tech companies are the worst of them.
Tier 5, Ports: As a hub of transportation, these areas provide guards, digitial security and lots of eyes and bodies. They have one of a kind scores.
Tier 6, Money Centers: Getting money and resources from banks and other highly secure businesses such as museums, casinos, jewelers and the like can be the most lucrative, and the most challenging.
Tier 7, Prisons: The most challenging heists can be getting onesself into and out of prison, as every level of security is employed and criminality is familiar.

Multiplayer:
With up to 4 players and a mastermind in a round, players are not able to use all 6 classes in a heist, and so must come up with a team with strengths and weaknesses. In addition to this, there is a NPC Mastermind role available in which a player has mastermind tools to control NPCs and thus control defenses for their building.

Story: The story would be about a ragtag of group of theives who redeem themselves taking it to the man and in the process find out their Benefactor was formerly working for the evil coproration that they're up against.

Minimum Viable Product:
A two person stealth action game, where one person plays plays an infiltrator/fighter and other plays a hacker/taker as they deal with patrolling senties, locked doors and trying to lower their suspicion levels.

Questions:
Any suggestions of other games I could look to for inspiration on systems and mechanics?
Any foreseeable problem with different classes feeling useful or balanced?
Does it sound fun?