I'm inclined to say that we're NOT supposed to be like Battlefield players in terms of taking hits, or any "modern" shooter. People are fleshbags, and they die easily. It makes sense that a blast of pretty much any weapon will kill someone in a game like Battlefield, because that's not unlike how things happen in real life.

Dust is different. We all have "dropsuits", which are fitted powered systems connected to a tactical netword, shields, and armor. Some suits even have "heavy armor". Further, we can take pains to improve our armor and shields at the base level, and install additional improvements to protect ourselves further. In a way, we're like mini-spaceships from EVE, outfitting ourselves for combat roles and trying to maximize our survival in many cases.

Weapons that have a Battlefield-like effect despite any of our modifications destroy this sort of balance and/or gameplay. If you die in a couple rounds regardless of your advancement, type of suit, and protective modifications - then any aspect of the "building your character" element is moot. You could just as easily do nothing with the suit, and just get the gun that allows you to do that.

Some weapons are intentionally lethal in very few shots, but they do so with certain trade-offs. Sniper rifles typically have a slow rate of fire, a very small clip, a scope that's inconvenient at short range, and abysmal hipfire. Shotguns can drop people quickly, but require you be very very close. Plasma Cannons will kill quickly, but are 1 shot at a time, arc-ing, slow, and only have 9 shots. Etc. etc.

TAR has needed some addressing because it does do that Battlefield bit, but does it with no real trade-offs. Short, long, precise scoped/hipfired... it is incredibly lethal, and combines those "general" all-round features with superiority at range, DPS, etc. So, it's sort of a perfect storm of flexibility, high damage, and being at the top tier in range.

I'd say you should be able to take a foe down fast... if they're lightly armored/shielded, you're head-shotting with certain weapons, etc. However, there's nothing wrong with gun battles taking more than a couple seconds. You're fighting people in armored suits, not fatigues.