The short answer is: there really is none and most people grit their teeth and deal with the new system

The longer answer is: some people hate RNG to the point that they'd prefer a mostly broken and tedious binary system that's full of issues because they hate the classic gaming sense of rolling some dice with modifiers.

Does it make it more 'tactical'? In a sense, yes. Does it makes it more fun? Depends on who you ask. Though I think it's clear what my stance on it is.

The binary system limits party coordination and build effectiveness, makes health a dump stat that means nothing no matter what the number is, and makes most niche builds and tactics and environment stuff mean little to nothing since armor blocks it all anyway. Oh, and it makes the game more like Diablo and Borderlands where loot is king and your actual build matters very little in the end...which also causes mages to lag behind physical damage dealers do to weapon scaling.

In an effort to mitigate the CC = King problem of mages being 'too' good (which is entirely subjective since you could make an unkillable warrior that could one shot anything in the game) in DOS1 they went way too far the other way.

Also, I'm having the sneaking suspisicion that where they originally seemed to have taken ques from D&D for game one, the stat inflation and loot priority and lack of focus on special effects imply inspiration from things like Diablo, Grim Dawn, or Path of Exile.