There are dynamics implemented within each RPG-styled game, and each will have their weaknesses and strengths. The developers probably based their end-content around the idea that this game really doesn't require any form of stealth gameplay. However, with that said, under the Ranger Skillset, there is an option to input skill points which allows you to get closer to your enemies while a bow is drawn. With that said, it is very easy to get extremely close to these enemies, but it is an absolutely pointless skill unless you have spent points in other parts of the Ranger Skillset to make the bow a more damaging weapon - in which case, there's no reason to get close to your enemy when that is done.
I can only imagine that skill is included for those who don't actually want to increase the Ranger Skillset and see it as a device to get closer to an enemy when they're apart from the mob.
I agree with your sentiment on what the concept of an RPG 'should' be, but all new RPG's don't follow that concept anymore, especially those which are action based RPG's. I mean, would you really consider being a thief in a game when you don't even need to worry about sneaking around? The last game I played where sneaking was even necessary was Splinter Cell. And even then, you didn't need to sneak in that game.
Sad times these are. For what Div II is though, it's definitely worth the money to me, as for this particular franchise and how it's been adapted, I'm happy enough with it.