I always salvage/sell post mission I keep a few different items for loadout variety, but barely fill much more than 50% of my inventory at a time.

I used to be a massive hoarder in ARPGS, but soon realised no point holding on to surpassed gear esp when they can become valuable crafting mats.

So yes while majority of the loot is junk its still useful junk, when broken down into mats or sold for a quick small cash boost.

I actually like it, its effectively extra loot. Same as what was in the mission and a small loot screen instead of the old loot boxes we used to have. As for OP complaining as to how to store everything, you may have missed there are buttons to mass sell and salvage types of gear. In any case, it wouldn't take you more than a couple seconds to organize your inventory, unless you have a physical disability with wrist/hand, in which case, you have my sympathy. This indeed will be a hard game.

The biggest problem is that weapons take the most space in the inventory.

When I have to get rid of them the other categories have barely filled.

Imho all items should just have the same size in the inventory grid.

Personally, I think even more weapons should drop.

Loot is the reason why I start an instance and fight my way through hordes of enemies. Without the promise of loot, why bother?

There could be separate missions, such as minning materials, such as the defense of a mining machine against monster waves, or even other players.

I have my own ideas as to "when" the player should be rewarded with loot in a mission / instance based game. But what can be said of ARPG's is that loot typically the main motivator for players to keep playing. Farming / Grinding / Earning, that's why you do the same things several times in an ARPG, not because the gameplay is 100% captivating. Top down games are fairly fun to play but they don't compete with FPS for stimulating braincells... What drives most players are the things we pick up and are rewarded with. 

In a sense i'm fairly relieved that there are such easy ways to sell / salvage all yellow items for eg. It's really not time a time consuming process. But in agreement with the author there does have to be a balance of resources, if you have too many crafting materials too readily available then it takes some of the pleasure out of it. On my last character I was up in the 100's of each type and that was after crafting maybe 100 of each equipment type to "min-max" everything I could. 

The problem is not the loot.  

The problem is that 99% of the loot is crap.  

If I want gear I do not look at my loot I just refresh the trader to get something decent.

At last for now.

Actually, in a lot of the lore good service in a mission is rewarded with a mastercrafted weapon, or a piece of wargear with a long lineage, be it a simple Guardsman holding the line against all odds or a Blood Angel overcoming the red thirst and carrying the day.

Inquisitors are notorious for it as well, throwing about pieces of rare archeotech like candy to any of their agents or proteges able to do more than chew, swallow, and not choke on their corpse-starch rations.

Seriously, some inquisitor lords are actually kind of obnoxious about it--who else in the Imperium gets away with "seconding" (in this case outright stealing) an Imperial Navy warship and giving it to his or her most trusted Inquisitor protege? "Look at me, I'm powerful, I'm abusing my power by hurting the war effort!"

More to the point though, the loot ties into one of the core concepts of the ARPG genre, which is pushing that little "I got stuff!" emotional button. It provides a reason to keep slogging through hordes of (frequently) same-y monsters in similar environments to keep playing and keep improving. Kinda like how MMOs changed over time from digital role-playing games where you played a character in character to ALL ABOUT THEM NUMBERS LOOK AT HOW HIGH MY NUMBERS ARE! and yet still manage to keep people playing--without that connection to their character, loot replaces it like... junk food for the mind.

But... it's an ARPG, and ARPGs are largely built around loot-pinatas. If you don't like the loot, stash it and see if maybe you get the itch for a character that can use it. I find it's been nice, as I've been cash/item strapped after the patch and it's been giving me stuff relevant to my current build that I can't buy or craft at the moment, so perhaps you're just having some unlucky RNG on the screen.