While the current system does add content, it’s artificial and most of the content is supposed to be in the gameplay anyways. People do like the current system, but the way my friends have described it as is being unfriendly to new players, as everything is RNG-based and makes it harder to get combinations you want to try out, and which also limits what characters you can use until way later in the game.
Personally, I like the current system because it’s unique and it adds something to do outside of the actual game, but that would easily be replaced by real customization and the ability to create a loadout that caters to your playstyle, which would lead to more variety in matches where everyone has a unique style and can select aspects for their loadout based on that. Overall, the current loadouts could do with more variety at the very least, like giving each mercenary more than 3 of each type of weapon or opening more weapon types to each merc.
I actually found systems like that in Payday 2 to be more intuitive because, while you still have to work to obtain different items and gear, you can customize your loadout to cater to your playstyle and general application, such as stealth, tanking, or accomplishing objectives, and the system feels far more fair, since you have control over how you progress.